MCP is not connecting to Claude

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1

Has anyone else had trouble reconnecting the Knack MCP integration in Claude?

I connected it successfully for the first time on July 24, and it worked normally with access to my Knack apps and tools. The next day, Claude said the connection had expired and needed to be reauthenticated. Since then, every reconnect attempt has failed after the Knack authorization step.

Claude shows:

“Your account was authorized, but the integration rejected the credentials it just issued.”

I also tested through Claude Code and found two additional issues:

  1. The public MCP endpoint advertises a protected resource on a different hostname.
  2. Knack’s OAuth registration endpoint rejects the localhost callback used by native clients such as Claude Code.

I have reported the issue to Knack with logs and reference IDs. I am mainly trying to determine whether anyone else is seeing the same reconnect failure.

2

Just tried their MCP and it doesn’t connect properly, its broken.

3

Hi all - We rolled out a fix today that allows Claude Desktop/Web to successfully authenticate to the Knack MCP Server… Everything should be working cleanly again now. Please let me know if you’re still seeing issues when you try to connect!

-John @ Knack.