I’m unable to find any requests matching that Request ID (neither 0aaddbbf-4b51-4542-b4fa-f4882814f436 from your screenshot nor 143ed5fb-d42a-49c9-8a74-16ebfffb67bf) on our end, which typically indicates the request never reached our backend systems.
Here are the things I would try to narrow it down:
Could you try running Network Diagnostics (Cursor Settings > Network > Run Diagnostics) and verify that all checks are passing? Please report any that fail.
Additionally, try setting your HTTP Compatibility Mode to HTTP 1.1 (Cursor Settings > Network > HTTP Compatibility Mode) and see if that resolves the issue.
If the error persists, can you open Developer Tools (Help > Toggle Developer Tools > Console) tab, try sending a message in the broken project, and share any red errors you see? That would help narrow it down.