Claude Troubleshooting Guide: Unable to Send, Model Unavailable, and Network Error Handling

The most annoying thing about using Claude isn’t not knowing how to use it, but when it suddenly “won’t send,” “keeps spinning,” or shows an overload message. The following Claude troubleshooting checklist is prioritized: first determine whether the issue is on the server side or your local side, then handle common failures like sending, login, and attachment uploads separately. Follow these steps and you can usually get back up within a few minutes.

Start with three quick checks: confirm whether Claude’s server is fluctuating

When you run into a Claude issue, don’t keep refreshing repeatedly and make things messier. First, switch networks (Wi‑Fi/mobile data) and turn off any proxy or blocking extensions—many “failed to load” cases are actually requests being blocked. Second, reopen Claude in an incognito window to rule out cache and extension conflicts. Third, check whether the same account is also abnormal on a phone/another device: if it fails everywhere, it’s likely congestion on Claude’s side and you’ll have to try again later.

Claude message send failures: handling overload, rate limits, and long inputs

If Claude shows “overloaded/please try again later,” the most effective approach is to reduce concurrency: stop asking from multiple windows at the same time, and wait dozens of seconds before sending again. If it’s “send failed but no error,” split an ultra-long input into two parts—especially when it contains lots of tables, code blocks, or pasted web page text, which more easily triggers risk controls and timeouts. You can also reframe the request as “give an outline first—then expand section by section”; Claude is more stable that way and it also saves time.

Model unavailable or conversation errors: switch chats and clear state

If you see “model unavailable/unable to complete request,” try starting a new conversation first; leftover ultra-long context in the old chat may cause Claude to keep getting stuck. If the new chat works normally, go back to the old chat and delete or shorten the most recent extra-long messages, then continue. If the browser side keeps showing a blank screen or buttons don’t respond, clearing the site cache and logging back into Claude usually restores it.

Login and verification issues: account, region, and browser blocking

If Claude login keeps redirecting in a loop or the captcha won’t appear, a common cause is third-party cookies being disabled or scripts being blocked. Temporarily lower the browser’s “block cross-site tracking/strict mode,” allow necessary cookies, then log in again. If a corporate or public network has many restrictions, switch to a clean home network for testing; if it opens but disconnects frequently, it’s often the network-layer session being interrupted rather than the Claude account itself.

Attachment/image upload failures: format, size, and one-shot submission strategy

When Claude attachment uploads fail, first check the three most practical things: whether the file is too large, whether the format is common, and whether the filename contains weird symbols. Save the document into a more universal format (such as PDF/PNG), and change multiple files into a single compressed archive or upload in batches for a higher success rate. After uploading, if the parsing result is clearly incomplete, don’t rush to re-upload—first ask Claude to repeat back the “number of pages/chapters it has read” to confirm what content it actually received.

If none of the above works, record a short reproduction sequence under the same network (including a screenshot of the error text, browser version, and whether you have any blocking extensions installed), then submit feedback. The more specific the information, the faster Claude can pinpoint the issue; otherwise, back-and-forth questions will only prolong recovery time.