Claude FAQ: Login verification failures, interrupted conversations, and file upload issues

When using Claude, the most frustrating thing is often not “not knowing how,” but suddenly being unable to log in, having replies cut off, or being unable to upload files. Below is a FAQ for Claude organized by the most common scenarios, using an actionable troubleshooting order to help you avoid detours. When you run into an issue, first follow the steps to self-check, then decide whether to contact support.

Can’t log in or stuck in a redirect loop: Check your browser and account status first

If Claude shows a login loop, a blank page, or keeps redirecting, it’s usually related to browser cache, extension blocking, or third-party cookies. First, open Claude in an incognito/private window, temporarily disable ad blockers/script extensions, and allow site cookies, then try again.

If you’ve switched networks (corporate network, campus network, proxy, etc.), it’s recommended to switch back to a stable network and log in to Claude again; some network policies can cause the authentication callback to fail. If it still doesn’t work, log out, clear the site data, and then log back in to prevent old session tokens from staying “stuck.”

Not receiving the verification code/verification email: Check filtering and delivery delays first

When Claude requires email verification, the code or email may be routed to Spam/Promotions or blocked by a corporate email gateway. First, search globally for the email subject/sender domain, add the relevant addresses to your allowlist, and then click “Resend.”

If you request verification codes multiple times in a short period, Claude may trigger a rate limit, which can appear as never receiving the code or being told to try again later. It’s recommended to wait a while before trying again, or use a more reliable email service to complete Claude verification.

Conversation interrupted, no response, or request error: Troubleshoot both content and network

If Claude stops halfway through a reply or keeps loading for a long time, common causes are network instability or an overly large context. You can first copy what you’ve written, refresh the page, and then split the question into two messages—especially for tasks like long-form rewriting or lengthy code reviews.

When Claude shows a request error, don’t rush to click Send repeatedly; continuous retries can worsen rate limiting. A steadier approach is to shorten the input, reduce the amount of text pasted at once, and avoid opening multiple tabs that make Claude process requests concurrently.

File upload fails or parsing is incomplete: Control format, size, and structure

If Claude fails to upload a file, first confirm the file format is common, the filename doesn’t contain special characters, and try converting it to a more universal export format. If it’s a scanned document or image-based PDF, parsing quality will be affected by clarity; consider increasing resolution or converting it into copyable text before giving it to Claude.

If Claude can upload but “doesn’t read everything,” it’s usually because the file is too large or the content structure is too complex. Split the file by chapter, keep only the page range needed for analysis, and clearly specify in your prompt “output the table of contents/key points first, then expand section by section”—this is often more stable than having Claude read everything at once.

Account restricted or additional verification required: Minimize unusual behavior triggers

If Claude suddenly asks for additional verification or shows an access-restricted message, first stop frequent logins/logouts, frequent network switching, or making a large number of requests in a short time. Stick to your commonly used device and browser and reduce behavior patterns that look “bot-like,” which often helps avoid repeatedly triggering risk controls.

If you truly can’t recover access, it’s recommended to submit a support request within the Claude page as prompted, including the approximate time it occurred, the browser you used, and screenshots of the error. The more complete the information, the easier it is for the Claude support team to pinpoint the issue and provide an actionable solution.