Claude FAQ: Account Registration, Subscription Fixes & Error Code Solutions

Claude is a powerful AI assistant developed by Anthropic. Many users encounter problems during registration, such as not receiving SMS verification codes, Plus subscription payment failures, or request throttling. This article summarizes the most common issues and step-by-step fixes to help you get back on track.

Account Registration & Login Issues

When registering for Claude, you need to provide a phone number to receive an SMS verification code. If the code doesn't arrive, first check whether your number supports international SMS. Try disabling spam filters or switching between Wi-Fi and mobile data. Users in China are advised to use a +86 number. If that still fails, try a different carrier or wait a few minutes before requesting again. If you see a "Account locked" message when logging in, it's usually triggered by multiple incorrect password attempts or login from a new location. Check your registered email for an unlock link and reset your password.

Subscription Failures & Payment Errors

Claude Pro is billed monthly. Common reasons for subscription failure include insufficient card balance, bank fraud prevention blocks, or mismatched billing addresses. Use a Visa or Mastercard single-currency card, and ensure the billing address matches the one on your bank account. If you see "Card declined," contact your bank to enable international payments, or try linking a PayPal account instead. If you're charged but the subscription doesn't activate, wait 15 minutes and refresh your account status—the system usually catches up automatically.

Common Error Codes & How to Fix Them

While using Claude, you might encounter error 429 (too many requests), which means you're sending requests too quickly. Pause for 10 seconds before retrying, or reduce your request frequency. Error 403 is often caused by IP restrictions—try turning off your VPN or switching to a different node. Error 500 indicates a temporary server glitch; refresh the page or try again later. If a conversation suddenly stops with a "Network connection error" message, check your local network and clear your browser cache. This usually resolves the issue.

Switching Devices & Data Sync

You can log into the same Claude account on both your phone and computer, but not simultaneously. When switching devices, your chat history syncs automatically. In rare cases, new devices may not show old conversations—simply refresh the page or log out and back in. If you see a "Session expired" message, just log in again. No data will be lost.