Can't connect Claude or ChatGPT
Updated November 1, 2026
How to fix the most common connection problems.
"Unknown client" or "Couldn't connect"
Shape lost the registration your AI app saved the first time it connected. Trying again won’t help. Remove the Shape connector, in ChatGPT under Settings → Apps & Connectors, then add it again. This is a one-time fix: it stays registered once you press Allow.
The link just opens this help center
shapecalendar.com/mcp is for apps to connect to, so a browser ends up here instead. For ChatGPT, add it from the plugin directory. For Claude, add a connector.
"Subscription required"
A workspace blocks it
On a ChatGPT Business, Enterprise or Edu workspace, an admin may have to allow Shape Calendar first.
New tools don't show up
Claude keeps a list of a connector’s tools. Open the Shape connector’s settings and refresh the tools list.