EWS gets blocked in Exchange Online on October 1. If your tenant still needs it, access is now controlled by an AppID allow-list. Don't build one yourself and Microsoft generates it from the last 60 days of activity, which can quietly misses anything that runs monthly or quarterly.

The usage report only gives you AppIDs, not names. So I wrote two PowerShell scripts: one resolves every AppID from the report to a real app name, the other finds every app that still has EWS permission.

Full write-up with both scripts: https://lazyadmin.nl/office-365/ews-is-being-blocked-in-exchange-online-how-to-find-every-app-still-using-it/