MCP OAuth login reports missing issuer although `iss` is present in callback

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

ChatGPT Powered by Codex & OWL Version 26.707.31428 Released 10 jul 2026 (codex-cli 0.144.1)

What subscription do you have?

ChatGPT Plus

What platform is your computer?

Microsoft Windows NT 10.0.19045.0 x64

What issue are you seeing?

Summary

OAuth authentication for the official Magnific MCP server fails in Codex CLI
0.144.1 on Windows.

Codex reports that the authorization response is missing the required issuer,
but the callback URL visibly contains the iss parameter with the exact
expected value.

Feedback ID:
019f5070-e26c-77d0-a7fe-255c2addc381

Environment

• Operating system: Windows
• Codex CLI: 0.144.1
• Codex Desktop: installed
• MCP transport: Streamable HTTP
• MCP server: https://mcp.magnific.com
• Authentication: OAuth

Configuration

[mcp_servers.magnific]
url = "https://mcp.magnific.com"
auth = "oauth"
enabled = true
default_tools_approval_mode = "prompt"

### What steps can reproduce the bug?

Feedback ID: 019f5070-e26c-77d0-a7fe-255c2addc381

### What is the expected behavior?

Codex should accept the matching iss value, exchange the authorization code,
store the OAuth credentials, and report the MCP server as logged in.

### Additional information

The same behavior is reproducible through Codex Desktop authentication and
through codex mcp login magnific.
Changing browsers and enabling or disabling two-factor authentication does not
change the result.
No manually supplied API key or bearer token is being used.