# Index row size 2856 exceeds btree when using OAuth to connect to MCP server

**URL:** https://stack.deel.com/t/index-row-size-2856-exceeds-btree-when-using-oauth-to-connect-to-mcp-server/538
**Category:** Bug Reports
**Created:** [July 27, 2026, 10:07am UTC](https://stack.deel.com/t/index-row-size-2856-exceeds-btree-when-using-oauth-to-connect-to-mcp-server/538 "2026-07-27T10:07:47Z")
**Posts on this page:** 1
**Page:** 1

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### Author: ![Krzysztof](https://avatars.discourse-cdn.com/v4/letter/k/ed655f/32.png) [@Krzysztof](https://stack.deel.com/u/Krzysztof)
#### Post date: [July 27, 2026, 10:07am UTC](https://stack.deel.com/t/index-row-size-2856-exceeds-btree-when-using-oauth-to-connect-to-mcp-server/538/1 "2026-07-27T10:07:47Z")

</div>

- Org name: [Doxy.me](http://Doxy.me)

- Details:  
We’re integrating with Deel’s MCP server (`https://api.letsdeel.com/mcp`) via OAuth.  
Discovery, dynamic client registration, and user authorization all succeed. The failure happens only at the token exchange step:  
**Request** : `POST https://api.letsdeel.com/oauth/tokens`  
**Auth** : public client (`token_endpoint_auth_method: none`) with PKCE  
**Response** : `401 unauthorized_client`  
**Error message:**