Claude Troubleshooting FAQ: Message Send Failures, “Context Too Long” Errors, and File Upload Limits

This guide covers the most common points where Claude gets stuck: message send failures, chats that suddenly slow down or disconnect, “context too long” warnings, and unstable file uploads or incomplete file reading. For each issue, you’ll find an actionable troubleshooting order to help you restore normal use without repeated trial and error.

Messages won’t send or keep spinning: check your network and browser first

If Claude shows “send failed/no response,” first check whether you have script blockers, ad blockers, or privacy-protection extensions enabled—these often interfere with requests. Next, try signing into Claude in an incognito/private window, or switch to a different browser engine (for example, moving from certain re-skinned browsers to Chrome/Edge).

If you’re on a corporate or campus network, intermittent failures may be caused by a proxy, gateway policies, or DNS tampering. The quickest comparison test is using a mobile hotspot. Once you confirm it’s a network issue, decide whether to switch networks or adjust proxy rules—so you don’t waste time repeatedly refreshing on Claude’s side.

Seeing “context too long”: break the conversation up and use summary handoffs

Claude can only process a limited amount of content per turn. If a single chat gets very long and you keep pasting large blocks of text, you’re likely to hit the context limit. The solution isn’t forcing more in—it’s splitting the task into a two-step “summarize—continue” flow: first ask Claude to condense the key information into bullet points, then start a new chat and use those points as the background to keep going.

A more reliable approach is feeding material in batches: share only a short section each time, and ask Claude to output structured notes (title, conclusions, items to confirm). This reduces context pressure and makes the results easier to reuse later.

File uploads fail or content is missing: control format, size, and structure

If Claude’s file uploads are unstable, first confirm the file format is common, the filename doesn’t include special characters, and avoid uploading very large files all at once. For scanned PDFs or image-based documents, text recognition depends heavily on clarity; you can convert to clearer images first, or export only the key pages and send those to Claude.

If you suspect Claude “missed” content, don’t just ask “did you read it all?” Instead, ask Claude to restate the table of contents/sections it saw, or point out the locations of key passages. By having Claude echo back what it actually parsed, you can quickly tell whether the upload failed, parsing was incomplete, or your prompt wasn’t specific enough.

Account anomalies and security/risk prompts: reduce frequent switching and unusual activity

Claude may occasionally trigger security policies due to frequent logins in a short time, frequent network-node switching, or automation-like behavior—showing up as more verification steps, session resets, or temporary unavailability. First, log out and log back in after clearing site cache and cookies, then avoid high-frequency use across multiple devices at the same time.

If the issue persists, save the error message, time of occurrence, and reproduction steps to help with follow-up diagnosis. Also copy important content to local storage promptly to avoid losing key drafts if a Claude session becomes unstable.