Claude FAQ: Login Restrictions, Message Failures, and Attachment Handling

What’s most frustrating about using Claude is often not not knowing how to use it, but suddenly being unable to log in, messages failing to send, or attachments stuck loading. Below, I break down common Claude issues by scenario and provide a troubleshooting order you can act on immediately, helping you avoid detours.

Can’t log in to Claude: stuck on verification, white screen, or infinite redirect

When Claude login is abnormal, first open claude.ai in an incognito window to test and rule out cache and extension interference; then switch to a different browser engine (for example, from certain domestic Chromium shell browsers to Chrome/Edge). If you see a white screen or repeated redirects, common causes are ad blockers, script extensions, or privacy plugins blocking the login callback. Temporarily disable the relevant extensions and try again.

Also confirm the network environment is stable and the router is not hijacking traffic; if you’re on a company/campus network, Claude may be affected by gateway policies—switching to a mobile hotspot is often a quick way to verify whether it’s a network-side issue. After logging in, it’s recommended to stick to one login method (the same email/the same third-party account) to avoid triggering risk controls because your Claude account “looks like it’s switching accounts.”

Claude won’t send messages: request error, endless loading, or overload notice

When a Claude chat message fails to send, first copy your prompt locally and refresh the page before retrying to avoid losing content. If you see something like “too many requests/please try again later,” it’s usually because you submitted too frequently in a short time or the service is busy. The most effective approach is to reduce how rapidly you send consecutive messages, cut down overly long context, and try again a few minutes later.

If Claude keeps spinning without an error, check first whether you enabled proxy split-tunneling, HTTPS interception, or browser security software; these tools can cause Claude requests to be rewritten by a middle layer. Switching the network back to the “most basic” direct-connection environment is often faster than repeatedly clicking retry.

Claude attachment upload failed: unsupported format, read failure, and permission issues

If Claude fails to upload a file, first check two things: whether the file is too large and whether the format is a commonly readable type (such as plain text, PDF, etc.). Running OCR on scanned PDFs and saving complex documents as more universal formats usually improves Claude’s parsing success rate significantly.

If Claude says you don’t have permission or the file can’t be read, a common cause is that the file comes from a cloud drive “online preview link” rather than a local file, or that the file download hasn’t completed. It’s recommended to save the file locally before uploading to Claude, and make sure the file isn’t encrypted or protected with an opening password.

Claude account restricted: frequent verification, unusual activity, and security advice

If Claude triggers frequent verification or restricts your account, the worst thing you can do is keep switching devices, IPs, and login methods to “brute force” it. A steadier approach is to disable suspicious extensions, keep a consistent network environment, confirm your email can receive messages normally, and maintain stable usage on the same device for a period of time so Claude’s risk controls can return to normal.

If you suspect your Claude account has been compromised, change your password immediately and sign out of other sessions; also check whether you’ve shared the account with multiple people. Multiple people using the same Claude account can easily trigger abnormal-login detection, and the more you try to log back in afterward, the more frequently you’ll be blocked.