Sign-In, Authentication, and Plan Issues

Sign-in problems are the most common reason a new user gets stuck before they have even sent their first message. The diagnostic process is simple if you know what to look at — and frustrating if you do not.

Start at the symptom that matches yours. Each section gives the likely cause and the fix.

Symptom: browser opens to authenticate but nothing happens

You ran claude (or clicked sign in in Desktop), a browser window opened, you signed in successfully — and then nothing. The browser sits there. The terminal or app stays on the loading screen.

Likely cause: the OAuth callback (the message that tells your local Claude installation that sign-in succeeded) is not reaching your machine. Usually a popup blocker, a firewall, or a corporate network policy.

Fixes in order of likelihood:

1. Allow popups for claude.ai in your browser settings, then try again
2. Try in a different browser. Safari, Chrome, and Firefox sometimes behave differently with OAuth callbacks
3. If you are on a corporate network, ask IT whether outbound connections to Anthropic are blocked or whether OAuth callback ports are restricted. This is the most common cause on managed work machines
4. Close the browser entirely (not just the tab), close Claude Code / Desktop, and try the whole flow fresh

Symptom: signed in successfully but Claude Code says "no plan recognised"

You signed in with the same account you use at claude.ai. claude.ai shows your Pro or Max plan correctly. But Claude Code claims you have no paid plan and refuses to start a session.

Likely cause: there can be a delay between Anthropic recognising a new subscription on the web side and propagating that recognition to Claude Code. Or, you signed in with a different account than the one holding the subscription.

Fixes:

1. In Claude Code, sign out and sign back in. This refreshes the plan check.
2. Check the email address shown in Claude Code. Make sure it matches the email of the account that has the subscription. Many users have multiple Anthropic accounts; only one has the plan.
3. If you just upgraded to a paid plan in the last few minutes, wait 5-10 minutes and try again. Plan changes are not always instant.
4. If still no joy after the above, sign out everywhere (claude.ai web, Desktop, Claude Code), wait two minutes, sign back in starting from claude.ai. This forces a clean session.

Symptom: Teams seat not provisioned

Your organisation has a Teams plan, the admin says they added you, but you cannot sign in to anything Teams-related. Or you sign in but get a free-tier experience.

Likely cause: Teams seat assignment requires the admin to invite you specifically and you to accept the invite by email. If the admin assigned a seat without sending an invite, or you did not click the invite link, the seat is allocated but not bound to your account.

Fixes:

1. Check your inbox (and spam folder) for an invitation email from Anthropic. Click the link to accept.
2. If no email arrived, ask your admin to re-send the invitation. They do this from the Teams admin panel.
3. Confirm the email address the admin invited matches the email you are signing in with. Mismatches are common when people have personal vs work accounts.
4. If you are on Team Standard and trying to use Claude Code: this will not work. Team Standard does not include Claude Code. You need Team Premium or above. The admin needs to upgrade the plan, not just assign a seat.

Symptom: "command not found: claude"

You installed Claude Code, but typing claude in a terminal returns "command not found" or similar.

Likely cause: the install completed but the claude command is not on your shell's PATH (the list of locations the shell searches for commands). This happens occasionally with npm installs and on some macOS configurations.

Fixes in order:

1. Close the terminal entirely and open a fresh one. The PATH is read at terminal start; a new terminal picks up the latest install.
2. If still missing, restart your machine. This refreshes everything.
3. If still missing after restart, you likely have a PATH issue. Switch to a different install method: if you used npm, try the native installer (curl -fsSL https://claude.ai/install.sh | sh) or Homebrew (brew install --cask claude-code) instead. These manage PATH for you.

Symptom: "you have used your free quota"

You are on the free tier, hit a usage limit, and now even simple messages are blocked.

Likely cause: the free tier has daily and weekly limits. Hitting them means waiting until the limit resets (typically next day or next week, depending which limit you hit), or upgrading.

Fixes:

1. Wait for the reset. The error message usually tells you when
2. Upgrade to Pro for $20/month — this dramatically increases the limit and unlocks Memory, Projects properly, MCP servers, Cowork, and Claude Code on Desktop
3. If your organisation has a Teams plan, ask the admin for a seat instead of using your personal free tier

Symptom: Claude Code keeps prompting for sign-in every session

You sign in, use Claude Code, close it, reopen — and it asks you to sign in again. Forever.

Likely cause: the local credential store is not retaining the session token. On macOS this is usually a Keychain issue; on Linux it is usually a file-permissions issue in ~/.claude/.

Fixes:

1. On macOS: open Keychain Access, search for "Claude" or "Anthropic", delete any matching entries, then sign in again. The next sign-in creates a clean entry.
2. On Linux/WSL: check ownership of ~/.claude/. It should be owned by your user, with normal permissions. If you accidentally ran claude with sudo at some point, the folder may now be owned by root and your normal user cannot write to it. Fix with: sudo chown -R $USER:$USER ~/.claude/
3. If neither works, fully uninstall Claude Code, delete ~/.claude/ (back it up first if you have content there), and reinstall. This is heavy-handed but reliable.

Symptom: API key works for development but not for Claude Code subscription

You have an Anthropic API key (separate from a subscription) and you are trying to use it for Claude Code, but Claude Code wants a subscription, not a key.

Likely cause: Claude Code can be configured to use either a subscription or an API key — but the configuration is different. By default it expects a subscription via OAuth. Using an API key requires explicit configuration via environment variables or settings.

Fix: set the ANTHROPIC_API_KEY environment variable in your shell, then start Claude Code. It should detect the key and use it instead of trying to authenticate via OAuth. Note that API usage is billed per token, separate from any subscription you may have. For most users a subscription is significantly cheaper than equivalent API usage.

When none of the above works

If your problem matches none of these symptoms, the right escalation is:

1. Check Anthropic's status page — sometimes the entire service is down and there is nothing you can do but wait. Search for "Anthropic status".
2. Check the version of Claude Code you have installed. Run claude --version. If it is several versions behind, update first — many issues are fixed in newer versions.
3. Search the Anthropic support site for the exact error message. Common errors usually have known fixes.
4. Open a support ticket with Anthropic, including the error message, the version of Claude Code, your operating system, and the steps you have already tried.

Most sign-in issues resolve in under five minutes once you identify which symptom you actually have. The diagnostic step that fails most often is the first one: people assume the problem and apply a fix without checking the symptom matches. Read the error message Claude Code is showing you, find it in the list above, and apply the matching fix in order.