Invalid session error on OAuth callback when accessing Atlassian MCP via proxy

[manikanta_ambati_accenture]

We are integrating Atlassian MCP Remote server with an IDE client (VS Code) and accessing it via a reverse proxy (Apigee) for security and logging.

The MCP initialization succeeds, but during the OAuth flow, the callback endpoint fails with an “invalid session” error.

The same setup works correctly when connecting directly to https://mcp.atlassian.com, without the proxy.

Error Details:
URL: mcp.atlassian.com/v1/callback?state=eyJzZXNzaW9uX2lkIjoiNDRlNzRjM2QtZDE1ZS00NWY4LTgxODYtZGUyOGQ0OGM5MjNkIiwib3JpZ2luYWxfcmVkaXJlY3RfdXJpIjoiaHR0cDovLzEyNy4wLjAuMTozMzQxOC8ifQ%3D%3D&code=eyJraWQiOiJBVVRIX...
Response: Invalid session

[Tomislav Tobijas]

Hey @manikanta_ambati_accenture ,

Just a note at the beginning that there's a dedicated Atlassian Rovo MCP Server forum discussion group where you'll probably get more responses about these kinds of topics and questions.
I'll ask mods if they can move this question there.

Anyway, I'm not an expert on this, but issues such as "invalid session" during OAth callback could be caused by:

• Mismatched Redirect URIs
• Session or Cookie Handling
• Base URL Configuration

You could check and ensure the callback/redirect URI is consistent and allowed in your OAuth app config.; check if Apigee is not modifying or stripping cookies, headers, or other parameters.
Also, if possible, allow the callback URI and check your network/proxy/firewall settings to ensure they're not interfering with the OAuth flow.

Here's this article that might help as well: Authentication and authorization 

Again, I haven't worked that much with the MCP server, so if anyone else stumbled upon this, feel free to chime in.

Cheers,
Tobi

[manikanta_ambati_accenture]

Thanks @Tomislav Tobijas 
I've posted my question there.

Also, I heard that the MCP server does not support registered OAuth2 apps from the developer console; please correct me if that's incorrect.