Some users may see an error when sending messages from BizChat and the BizChat side pane in Microsoft 365 apps.

Title: Some users may see an error when sending messages from BizChat and the BizChat side pane in Microsoft 365 apps. User impact: Some users may have seen an error when sending messages from BizChat and the BizChat side pane in Microsoft 365 apps. More info: More info: Affected Microsoft 365 apps included: Outlook on the web Outlook desktop Microsoft Teams Affected users may have seen an error stating “something went wrong.” This issue affected users that had selected the Opus 4.8 model. Final status: We’ve determined that a recent update intended to enable an updated AI model used to process chat requests and generate responses, Opus 4.8, caused an unexpected influx of service requests that led to the impact. We’ve reverted the offending update and confirmed from service telemetry that this issue is resolved. Scope of impact: Some users located in the Asia Pacific or South America regions sending messages from BizChat and the BizChat side pane from an affected M365 app may have been impacted. Start time: Thursday, July 23, 2026, at 1:23 AM UTC End time: Thursday, July 23, 2026, at 4:38 AM UTC Root cause: A recent update intended to enable an updated AI model used to process chat requests and generate responses, Opus 4.8, caused an unexpected influx of service requests that led to the impact. Next steps: We’re reviewing our validation and updating procedures to better detect and prevent issues like this prior to deployment in the future. This is the final update for the event.

Title: Some users may see an error when sending messages through the BizChat side pane in multiple M365 apps User impact: Some users may see an error when sending messages through the BizChat side pane in multiple M365 apps. More info: Affected M363 apps include, but may not be limited to: Outlook on the web Outlook desktop Microsoft Teams Affected users may see an error stating “something went wrong.” Current status: We're investigating a potential issue in which some users may see an error when sending messages through the BizChat side pane in Outlook on the web and Outlook desktop and checking for impact to your organization. We'll provide an update within 30 minutes. Scope of impact: Some users located in the Asia Pacific or South America regions sending messages from the BizChat side pane from an affected M365 app may see an error stating “something went wrong.” This information may be updated as our investigation continues. Next update by: Thursday, July 23, 2026, at 6:00 AM UTC

Title: Some users may receive an error when sending messages with the Microsoft Copilot Chat side pane User impact: Users may receive an error when sending messages with the Microsoft Copilot Chat side pane. More info: Specifically, when attempting to send messages within the Copilot Chat side pane in Outlook on the web and Outlook desktop users receive an error that states, “Something went wrong.” Current status: We're investigating a potential issue in which some users may see an error when sending messages through the Copilot Chat side pane in Outlook on the web and Outlook desktop and are checking for impact to your organization. We'll provide an update within 30 minutes.