If an account rejects a +86 number, buying a +852 or US number is not automatically the next step. Read whether the message rejects the phone number, the user’s location or the account itself. A travel data eSIM changes your data connection; it does not necessarily provide any number that can receive SMS.
What another SIM can and cannot change
| Question | Useful check |
|---|---|
| Does the plan include a number? | Look for incoming SMS and voice service, not just a destination and GB allowance. |
| Can you activate it where you are? | Ask the carrier about initial activation, registration and roaming before payment. |
| Will the app accept it? | Claude excludes several number types, including VoIP and app-generated numbers. Carrier SMS capability alone does not prove acceptance. |
| Can you keep it? | Check renewal, number expiry and replacement. A one-time rental gives no future control. |
A code is not identity verification
Anthropic’s identity-verification guidance describes checks that may require an original government photo ID and a live selfie; organizations can be asked for business details. A phone number bought from another country cannot supply those facts. Use your own accurate details in the official flow.
When delivery is the actual problem
For a number you are eligible to use, confirm it is active, receives normal SMS and is registered on a supported network. Wait for the resend timer and use the latest code. If the app says the number is already attached to another account, contact the app’s support with that message rather than assuming the SIM is defective.
Do not buy a number bundle before checking whether your chosen Codex account even asks for a phone. Registration steps can differ from a coding client’s sign-in. Start with the actual prompt, then solve that specific requirement.