[BUG] Atlassian MCP Server Connection Timeout (SSE)

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

Most Probable Causes:

1. Atlassian's MCP service is having issues

• Their endpoint might be overloaded, in maintenance, or buggy
• You're not the only one - this is likely affecting other users too

1. Network infrastructure blocking SSE

• Some corporate firewalls or ISPs block long-lived HTTP connections
• The connection starts but gets silently dropped before completing

1. Service compatibility issue

• There might be a version mismatch between Claude Code's MCP client and Atlassian's server
• The handshake protocol might have changed

Why basic tests pass but MCP fails:

• A simple curl test just checks "can I reach this URL?" (YES)
• The MCP connection needs to complete a complex handshake with auth tokens and keep the connection alive (NO)

Bottom Line

What's broken: The Atlassian MCP server endpoint isn't responding to connection requests, even though authentication works.

What you can't control: This is likely a server-side issue with Atlassian's MCP service or network infrastructure between you and them.

What you've already tried (correctly): Re-authentication and restarts won't help because the auth is working - it's the connection that's failing.

What Should Happen?

1. Authentication (currently working):

• You authenticate with Atlassian
• Claude Code receives OAuth tokens
• Tokens are stored securely

1. Connection (currently broken):

• Claude Code sends the auth tokens to mcp.atlassian.com
• The Atlassian MCP server should immediately respond with:
• A list of available tools (e.g., "search Jira", "create ticket", "view Confluence pages")
• Connection acknowledgment
• The SSE connection stays open for real-time updates

1. Usage (can't get here):

• You'd be able to use Atlassian tools in Claude Code
• Example: "Show me my Jira tickets" or "Search our Confluence docs"
• Claude would have direct access to your Atlassian workspace

Error Messages/Logs

Steps to Reproduce

Steps to Reproduce

14 -1. Configure Atlassian MCP server in Claude Code
15 -2. Authenticate with Atlassian (authentication succeeds)
16 -3. Start Claude Code session
17 -4. Run /mcp command or wait for automatic connection
18 -5. Connection consistently times out after 30 seconds

Claude Model

Other

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.1.23

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_