Codex App: new task creation times out when configured MCP server is unreachable

What version of the Codex App are you using (From “About Codex” dialog)?

26.623.141536

What subscription do you have?

ChatGPT Pro

What platform is your computer?

Darwin 25.5.0 arm64 arm

What issue are you seeing?

Immediately after updating Codex Desktop to version 26.623.141536, I could no longer create new chats.

Every attempt failed with:

• Task creation failed — Timeout
• Chat startup failed — Timeout

Existing chats continued to work normally.

After investigating, I found that the issue was caused by an MCP server configured with a LAN-only endpoint.

When working outside my local network, that MCP server became unreachable. As a result, Codex waited for the MCP connection and eventually timed out, preventing any new task from being created.

After replacing the LAN-only MCP endpoint with a reachable Tailscale MagicDNS endpoint and restarting Codex, new chats worked immediately.

Expected behavior:

If an MCP server is unreachable, Codex should mark that MCP as unavailable, display a warning if necessary, and continue creating the task.

Actual behavior:

A single unreachable MCP server prevents all new task creation until timeout.

This behavior appears to have started after updating to version 26.623.141536.

What steps can reproduce the bug?

Feedback ID: no-active-thread-019f3add-322f-7703-b72a-f7c57de75730

What is the expected behavior?

If an MCP server is unreachable, Codex should mark that MCP as unavailable and continue creating the task instead of failing with a timeout.

Additional information

Feedback ID: no-active-thread-019f3add-322f-7703-b72a-f7c57de75730

The issue was resolved by replacing the LAN-only MCP endpoint with a reachable Tailscale MagicDNS endpoint.

This suggests that Codex currently blocks new task creation while waiting for an unreachable MCP server instead of treating it as unavailable.