Answer first: A verification code can fail to arrive because a platform has limited the request, rejected or restricted the phone number, restricted the account, or encountered a delivery or environment problem. The useful clue is the platform’s own error or guidance: it identifies whether the restriction attaches to a request, a number, an account, or the route to the device. This guide separates only conditions documented by the named platforms, with the source-check date beside each claim.
Start with the restriction’s scope
Do not assume that a missing message proves a problem with a phone number. A platform can stop a repeated request, keep an account under a temporary block, require a particular number type, or have a delivery issue after accepting the request. The distinction changes what its own recovery instructions say.
This is an after-the-failure guide. If the platform has shown a policy about number eligibility, the verification compatibility index covers that policy detail without turning this page into a platform ranking. For general verification routes, see verification options.
Restrictions on the request
For Microsoft, excessive or repetitive requests to alternative emails or phone numbers can lead it not to send verification codes. Its guidance says waiting a day can be enough to remove a block and, if nothing changes after 24 hours, waiting longer, up to one week.
Fiverr documents a maximum of five verification-code requests within 24 hours and says to wait 24 hours after exceeding that limit. It separately advises allowing up to 10 minutes for a code to arrive; requesting another code before that window ends may reset the process or lead to a temporary block.
Steam says it can stop sending SMS messages when too many have been sent to the recipient. Its published recovery is to wait from a few minutes to an hour before trying again.
Discord documents this timeout as phone-number-scoped: “the phone number was recently used and is currently in a timeout period.” Its published recovery is: “Please wait 24-48 hrs before verifying your phone number once more.”
On Snapchat, the literal “Too many requests” error appears in two separate flows. Its contact-method verification article says to wait 24 hours, while its login-code article says to wait a few minutes and confirm the network connection is stable. Those are distinct published recovery instructions, not one combined window.
The practical step is narrow: stop repeating the request and use the wait period the platform actually publishes. A wait documented for one platform is not evidence of the same limit elsewhere.
Restrictions on the number
Google documents two separate phone-number limits: the number of accounts a phone number can create and the number of times a phone number can be used for verification. Its help page presents the errors “This phone number cannot be used for verification” and “This phone number has been used too many times for verification,” with a different number as the stated remedy rather than a documented wait.
At ID.me, the identity-verification requirement is a phone number associated with a physical SIM on a carrier network, and Voice-over-IP numbers cannot be used. That is an eligibility rule for the number, not a diagnosis of why a particular message was withheld.
Telegram’s FAQ says accounts can only be connected to a mobile number and that landlines are unsupported. The same official documentation also describes a separate non-SMS sign-up path using anonymous numbers on Fragment. Those statements need to stay together: the mobile-number rule does not describe every Telegram account-creation path.
For Discord, VoIP and landline numbers cannot be used for its verification flow. This is Discord’s published eligibility rule for the phone number; it does not identify a detection method or explain a specific missing message.
The X help page publishes two separate limits: “Your X account can only have one phone number attached to it,” while “You can add your phone number to up to 10 accounts.” The first rule attaches to the account; the second attaches to the phone number. Neither rule has a published wait period.
Separately, Snapchat says, “Only one email and mobile number can be verified per Snapchat account.” Its page also says the same contact information cannot be shared across multiple accounts. This number-and-account rule is separate from Snapchat’s request-throttle guidance.
When a platform names a number-specific rule, treat that as the scope of its published rule only. It does not reveal the platform’s internal detection method or establish the cause of any individual non-arrival.
Restrictions on the account
Microsoft says, “we might interpret it as potentially risky behavior,” leading to a temporary block where it will not send codes. Its page also describes a 30-day restriction after certain security-information changes.
On Upwork, a phone number associated with an existing account will produce an error when used for a new account. Its published route is account recovery; the page does not provide a fixed waiting period.
Fiverr’s policy says one phone number can be linked to one Fiverr account. Its page says a number associated with another account cannot be used again, including when that account is disabled. That is an account-association rule, not a delivery-delay explanation.
In X’s guidance, a number can be automatically detached from an account when it has been “inactive for 45 or more days” and that number is added to a new account. This is a published account-and-number pairing trigger, not a recovery wait.
Etsy’s two-factor authentication guidance requires a password and verification code on a new browser or device and “every 30 days.” That is an account re-verification cadence, separate from Etsy’s regional availability guidance.
Account restrictions can look like delivery failures from the user’s side because no useful code arrives. The published messages and recovery routes are more reliable clues than guessing which state a platform assigned.
Delivery and environment checks
Microsoft lists regions where its SMS service has limited functionality or is temporarily unavailable, a full message inbox, malfunctioning messaging apps, and text blocking for unknown numbers as possible reasons a verification SMS might not appear.
Upwork says a code should be sent instantly; its guidance is to check that the phone number is correct and that service coverage is working if it is not delivered within a few minutes.
Steam advises checking whether the phone inbox is full and also calls out an incorrect international format or country code. Telegram likewise tells users to enter a mobile number in international format.
Apple notes that if access to trusted devices or a trusted phone number is temporarily unavailable, account recovery can take a few days or longer. This named trusted-number page did not specify line type when checked on 9 August 2026.
GitHub’s regional eligibility list for SMS two-factor authentication says GitHub “only supports two-factor authentication via SMS for certain countries” and directs people outside that list to a TOTP authenticator app. The list is platform-specific, so it is not reproduced here.
Coinbase tells users who do not receive a six-digit SMS code when expected to “wait 30 seconds and select Resend code.” Its current troubleshooting page does not identify the restriction as number-scoped or account-scoped.
Etsy’s regional list for call and text verification says that “receiving a verification code to your phone may not be available” depending on the country. Its stated alternative for a country outside the list is an authenticator app; the country list is not reproduced here.
Wise recommends checking that “your device can receive texts,” the registered phone number is being checked, and phone signal is available. It also lists procedural steps such as restarting the phone or trying a local carrier while international roaming; no fixed wait is documented.
Evidence table: what each platform actually documents
Every row lists the platform’s published wording, what the restriction attaches to, its evidence class, and the date checked. Quotes are short excerpts from platform documentation, not general policy for other services.
| Platform | What is documented | Restriction attaches to | Documented wait or recovery | Evidence class | Checked |
|---|---|---|---|---|---|
| Microsoft | “Don’t make excessive or repetitive requests” because it can block code delivery. | Account | Wait a day; if unchanged after 24 hours, wait longer, up to one week. | Published throttle | 2026-08-09 |
| “This phone number has been used too many times for verification.” | Phone number | Use a different number; no wait documented. | Published throttle | 2026-08-09 | |
| Fiverr | “only one phone number can be verified every 24 hours” | Phone number | No recovery window documented for this rule. | Published throttle | 2026-08-09 |
| Fiverr | “You can only request a verification code up to 5 times within a 24-hour period.” | Unspecified by the page | “wait 24 hours before trying again” after exceeding this limit. | Published throttle | 2026-08-09 |
| Steam | “Steam will also stop sending SMS messages if too many have been sent to you” | Account or recipient | Wait a few minutes to an hour. | Published throttle | 2026-08-09 |
| Upwork | A number associated with an existing account produces an error for a new account. | Phone number and account association | Account recovery; no fixed wait documented. | Published eligibility rule | 2026-08-09 |
| ID.me | “Your phone number must be associated with a physical SIM on a carrier network.” | Phone number | No wait documented. | Published eligibility rule | 2026-08-09 |
| Telegram FAQ and Telegram blog | “Telegram accounts can only be connected to a mobile number”; Telegram also describes an anonymous-number path on Fragment. | Phone number and account path | No wait documented. | Published eligibility rule | 2026-08-09 |
| Discord | VoIP and landline numbers cannot be used for verification. | Phone number | No recovery window documented for this eligibility rule. | Published eligibility rule | 2026-08-09 |
| Discord | “the phone number was recently used and is currently in a timeout period.” | Phone number | “Please wait 24-48 hrs before verifying your phone number once more.” | Published throttle | 2026-08-09 |
| Apple | “Account recovery might take a few days or longer.” | Account recovery | Wait for recovery; no fixed duration. | Published delivery troubleshooting | 2026-08-09 |
| GitHub | SMS two-factor authentication is supported only for certain countries. | Region | Use a TOTP authenticator app if outside the published list; no wait documented. | Published eligibility rule | 2026-08-09 |
| Coinbase | “wait 30 seconds and select Resend code.” | Unspecified by the page | Wait 30 seconds, then select Resend code. | Published delivery troubleshooting | 2026-08-09 |
| X | “Your X account can only have one phone number attached to it.” | Account | No wait documented. | Published eligibility rule | 2026-08-09 |
| X | “You can add your phone number to up to 10 accounts.” | Phone number | No wait documented. | Published eligibility rule | 2026-08-09 |
| X | A number can be detached after 45 or more inactive days when it is added to a new account. | Account-and-number pairing | Eligibility trigger; no recovery wait documented. | Published eligibility rule | 2026-08-09 |
| Snapchat | “Only one email and mobile number can be verified per Snapchat account.” | Phone number and account | No wait documented. | Published eligibility rule | 2026-08-09 |
| Etsy | Phone verification may not be available depending on the country. | Region | Use an authenticator app if outside the published list; no wait documented. | Published eligibility rule | 2026-08-09 |
| Etsy | A verification code is required on a new browser or device and “every 30 days.” | Account | Re-enter the verification code at those events; no wait documented. | Published account-state rule | 2026-08-09 |
| Snapchat contact verification | “Too many requests” after SMS-code requests. | Request; subject otherwise unspecified | Wait 24 hours. | Published throttle | 2026-08-09 |
| Snapchat login code | “Too many requests” after SMS-code requests or multiple login attempts. | Request; subject otherwise unspecified | Wait a few minutes and ensure the network connection is stable. | Published throttle | 2026-08-09 |
| Wise | Check that the device can receive texts, the registered number, and phone signal. | Unspecified by the page | Follow the listed device, signal, roaming, or alternate-channel steps; no fixed wait documented. | Published delivery troubleshooting | 2026-08-09 |
When this guide cannot diagnose the problem
This guide cannot determine an undocumented platform rule, a current platform outage, a carrier-specific routing event, or the state of a particular account. It also cannot turn an eligibility policy into an explanation of a specific missing message. If the displayed error, entered international format, coverage, inbox state, and published wait do not match a row above, use the platform’s support path and record the exact error rather than applying a diagnosis from another service.
Methodology and known gaps
Every platform claim above was checked against the canonical first-party URL on 2026-08-09. Rendered browser pages were used where available; Discord, Fiverr, and Upwork were positively verified with standard desktop-browser requests after their help centers showed a browser challenge, while the six added platform pages were verified from server-rendered responses using that request pattern when browser automation was unavailable. The evidence labels distinguish published eligibility, throttle, account-state, and delivery-troubleshooting documentation. They do not assert a platform’s detection mechanism or the reason a particular message failed.
WhatsApp is omitted from the evidence table because the available page was served in Thai and its English wording could not be verified. OpenAI is also omitted because bot protection blocked retrieval, so verification could not be completed and this guide makes no claim about its policy in either direction. Apple is deliberately described only at page scope: its named trusted-number page did not specify line type when checked on 2026-08-09.
Sources
- Microsoft, Common problems with two-step verification for a work or school account, checked 2026-08-09.
- Google, Phone number verification, checked 2026-08-09.
- Fiverr, Phone verification: Secure your Fiverr account, checked 2026-08-09.
- Steam, Steam Support FAQ, checked 2026-08-09.
- Upwork, How to verify your phone number on Upwork, checked 2026-08-09.
- ID.me, Technical requirements to verify your identity, checked 2026-08-09.
- Telegram, FAQ and Ultimate privacy, topics 2.0, checked 2026-08-09.
- Apple, Get a verification code and sign in with two-factor authentication, checked 2026-08-09.
- GitHub, Countries where SMS authentication is supported, checked 2026-08-09.
- Coinbase, Two-step verification troubleshooting, checked 2026-08-09.
- X, Phone number FAQs, checked 2026-08-09.
- Etsy, How to Make Your Account More Secure, checked 2026-08-09.
- Snapchat, I can’t verify my email or mobile number and I can’t receive my code to log into Snapchat, checked 2026-08-09.
- Wise, I can’t use my 2-step verification method, checked 2026-08-09.
- Discord, How to Verify Your Discord Account, checked 2026-08-09.
