Launcher Cannot Connect/Verify Ownership (0x89245111, 503, 429)

Description of the issue:
When launching the Minecraft Launcher, it successfully downloads background updates and core files, but fails to authenticate my Xbox account. It displays a red banner stating: "Oh no! Something went wrong, and we couldn't connect to the Minecraft services." The launcher_log.txt shows the server returning "HTTP 503 Service Unavailable" and subsequently "HTTP 429 Too Many Requests" due to repeated connection attempts. When trying to switch to another purchased account, error code "0x89245111 (Swamp) - Unable to get token" appears. Xbox Support has instructed me to submit this bug report for further backend investigation.

Steps to reproduce:

1. Open the Minecraft Launcher (v2.6.2).

2. Attempt to log in with a valid Microsoft/Xbox account that owns Minecraft Java Edition.

3. Observe the red error banner at the top of the launcher preventing game access.

4. Attempt to switch to a different account or create a new Windows user profile and launch again.

Expected result:
The launcher should successfully authenticate the account, verify game ownership, and allow the user to launch Minecraft Java Edition.

Actual result:
Authentication fails with a red error banner. The launcher is blocked by HTTP 503 and 429 errors, and occasionally shows error code 0x89245111 (Swamp). The issue persists across different accounts, completely different Windows user profiles, and even when remoting into a completely different PC on a separate network.