Gmail:search_threads is unable to authenticate despite repeated attempts

### MCP server URL or name

https://gmailmcp.googleapis.com/mcp/v1

### How are you connecting to this server?

From a custom connector URL I entered manually

### Where does the issue occur?

During a conversation (after initial auth)

### When did you last reproduce this?

10 May 2026 - 1505 US Eastern Time (1805 UTC)

### Browser and OS

Chrome, Windows 11

### Describe the issue

search_threads is failing to receive permission.
I have disconnected and reconnected the custom connector 5 or 6 times.
I have deleted the connector and recreated it 2 or 3 times
I have recreated the client with a new secret on the google side.
I have checked scope and given everything under the sun on the google side.
I have authenticated and reauthenticated.
I have deleted the third party apps and services.
nothing I do seems to get it to connect.

I'm reasonably sure I'm doing something wrong, but at this point, I can't imagine what.
Is there something further I should check?

### Error details

```shell
The error returned was simply:

"This connector requires additional permissions. The user needs to reconnect it with the appropriate access."

That's the full error — there are no additional error codes, HTTP status codes, or stack traces surfaced from the MCP layer to me. What you can put in a ticket:

Connector: Gmail (gmail2 / https://gmailmcp.googleapis.com/mcp/v1)
Tool called: Gmail:search_threads
Query params: { query: "is:unread in:inbox", pageSize: 50 }
Error message (verbatim): "This connector requires additional permissions. The user needs to reconnect it with the appropriate access."
Likely cause: The OAuth2 scope granted during initial authorization is likely missing https://www.googleapis.com/auth/gmail.readonly (or equivalent read scope). The connector may have been authorized with a narrower scope than what search_threads requires.
Expected fix: Re-authorizing the connector and ensuring the Gmail read scope is granted during the OAuth consent flow.
```

### Expected behavior

prompt was "use the gmail2 connector to see how many unread emails I have"
expected behaviour was to see a number.

### Additional context

_No response_