Some users may be unable to access https://m365.cloud.microsoft and receive an error

Title: Some users may be unable to access https://m365.cloud.microsoft and receive an error User impact: Users may be unable to access https://m365.cloud.microsoft and receive an error message. More info: Users received a "GetSections returned no conversation history" error message. Final status: Further analysis indicated that the previously referenced 400 and 503 error messages were unrelated to the issue described in this communication, and we've updated the communication accordingly. We reverted a recent service update that was intended to improve chat-loading functionality when accessing m365.cloud.microsoft and confirmed through service telemetry that the error rates have subsided and service is restored. Scope of impact: This issue may have affected some users attempting to access https://m365.cloud.microsoft. Start time: Tuesday, September 8, 2026, at 4:30 AM UTC End time: Tuesday, September 8, 2026, at 5:15 PM UTC Root cause: A recent service update, intended to improve how chats are loaded when accessing m365.cloud.microsoft, rejected requests which resulted in https://m365.cloud.microsoft failing to load. Next steps: - We're reviewing our testing processes to determine how we can identify similar issues prior to deployment so we can resolve these issues beforehand. This is the final update for the event.

Title: Some users may be unable to access https://m365.cloud.microsoft and receive an error User impact: Users may be unable to access https://m365.cloud.microsoft and receive an error message. More info: Users receive either a 400 or 503 error code, or a "GetSections returned no conversation history" error message. Current status: We've received reports of an issue where users receive either a 400 or 503 error code, or a "GetSections returned no conversation history" error message when attempting to access https://m365.cloud.microsoft. We're reviewing a HTTP Archive (HAR) file from both working and non-working scenarios to assess where the issue lies. Scope of impact: This issue may affect some users attempting to access https://m365.cloud.microsoft. Next update by: Tuesday, September 8, 2026, at 6:00 PM UTC

Title: Some users can't access https://m365.cloud.microsoft and receive an error User impact: Users can't access https://m365.cloud.microsoft and receive a 400, 503 error code, or a specific error message. More info: Users receive either a 400 or 503 error code, or a "GetSections returned no conversation history" error message. Current status: We're investigating a potential issue with accessing https://m365.cloud.microsoft and checking for impact to your organization. We'll provide an update within 30 minutes.