Spring Lake Park Schools

Title: Some users' mailbox syncs may fail with an error in Exchange Online User impact: Users' mailbox syncs may fail with an error in Exchange Online. More info: Users see the following error message in Microsoft Graph: "HTTP 400 -- Operation not allowed -- Operation on Non IPM Subtree forbidden." Current status: We've identified a recent code change made to specific mailbox APIs which is resulting in the error messages seen in Microsoft Graph when these apps access non-Interpersonal Messaging (IPM) mailboxes. We're reverting this change to verify that it's the source of this issue and to fully remediate impact. Scope of impact: This issue may affect some users' mailbox syncs, specifically for customers using apps that access non-Interpersonal Messaging (IPM) mailboxes through Microsoft Graph, which returns an error code in Exchange Online. This information may be updated as our investigation continues. Next update by: Wednesday, October 14, 2026, at 10:30 PM UTC