Troubleshooting

Start with the message you see. Each assistant’s setup page also has its own troubleshooting table.

On Nylon’s consent screen

You see	Why	Fix
Upgrade to Adviser	Your seat is Starter, which doesn’t include AI-assistant connections.	Ask your Nylon admin for an Adviser or Elite seat. Then connect again from your assistant: the earlier attempt was cancelled.
AI tool connections are turned off for your account — contact your administrator.	Your admin has switched off Allow AI tool connections.	Ask them to turn it on in Organisation Settings → Connections, then connect again.
A sign-in page, again and again	Your browser isn’t keeping you signed in to Nylon, or the sign-in took more than about 10 minutes.	Sign in to Nylon in the same browser first, then start the connection again from your assistant.

Check your seat under Account → Products & Billing in Nylon. Seats on a plan Nylon no longer sells don’t include AI-assistant connections.

In your assistant

Problem	Fix
The assistant can’t add Nylon, or the option is missing	Your assistant plan or workspace settings may not allow custom connectors. See the setup page for Claude, ChatGPT or Copilot Studio.
Claude’s sign-in fails straight after adding Nylon	Remove the connector and add it again, choosing Register automatically under OAuth client.
The assistant answers without using Nylon	Switch Nylon on for the chat, and start the prompt with “Using Nylon”. Name the jurisdiction too.
Results come from the wrong country	Name the jurisdiction in your question (“in New Zealand”, “under UK tax law”) so the assistant can filter to it.
Citation links ask you to sign in	That’s expected. Links open Nylon’s source viewer, which needs a Nylon account. Anyone you share the answer with needs their own Nylon sign-in to follow them.
Nylon asks you to sign in again	Your sign-in lapses after 30 days without use, or after your admin changed your access. Reconnect from your assistant.
Tools stopped working after an admin change	Removing access takes effect within an hour. Once your admin restores it, the assistant can usually carry on; if it doesn’t, reconnect.

For developers

Problem	Fix
400 invalid_client_metadata at registration	Your client’s redirect URL isn’t registered. See Other MCP clients.
429 temporarily_unavailable on refresh	Temporary rate limiting. Back off and retry with the same refresh token; don’t discard it.
invalid_grant on refresh	The refresh token was already used, expired or revoked, or the user lost access. Sign the user in again.
404 Session not found	The session expired, was closed or the server restarted. Send a new initialize.
401 with a valid-looking token	The token has expired or was issued for a different resource. Refresh it, sending resource=https://mcp.usenylon.com/mcp.
Sign-in fails in a web app	Nylon’s sign-in endpoints don’t allow cross-origin browser requests. Run sign-in on a server or in a native app.

Still stuck? Email support@usenylon.com with your assistant’s name, what you tried and any request ID from the error.