Atlassian MCP auth fails in Copilot Desktop with:

Atlassian MCP auth fails in Copilot Desktop with:

`Incompatible authorization server: authorization server advertised an issuer that does not match the URL its metadata was discovered from (RFC 8414 §3.3)`

Exact error after clicking on sign-in: "Authentication failed

Atlassian: RPC error -32603: Request session.mcp.oauth.login failed with message: Incompatible authorization server: authorization server advertised an issuer that does not match the URL its metadata was discovered from (RFC 8414 §3.3); refusing to connect"

Endpoint: `https://mcp.atlassian.com/v1/mcp`

Worked previously; started after re-auth prompt.

Repro: Add MCP server → click Sign in → fails immediately.

---
| Field | Value |
| --- | --- |
| App version | 1.1.9 |
| OS | Windows 10.0.26200 |
| Theme | GitHub |
| Path | /chat |
| Tenure | Day 5 (Week 1) |

まず、報告された Windows 環境の Copilot Desktop で https://mcp.atlassian.com/v1/mcp のサインイン失敗を再現し、次に MCP OAuth のログインパスと RFC 8414 メタデータの処理を追跡します。完了条件は、Atlassian MCP サーバーを追加でき、issuer-mismatch エラーなしでサインインが完了することです。

索引モデルが issue の本文から書いたものです。