We still have not heard any update from Microsoft on the
thread opened by our team and the issue is not reproducible in the numerous tests our engineers performed. There are quite a lot different services, tuning options, and settings on Microsoft's end. A guess of our engineers is that it might be related to a location-based restrictions. At this point, from Plesk's end we have an initiative to update the msgraph-sdk-php library version. However, as I previously pointed out, that requires significant rework and it has no guarantee it will solve the issue. The ETA for it is Plesk 18.0.70 (which is not set in stone). I would like to appeal once again to everyone who is experiencing the issue to also report it on Microsoft end, so it can be paid more attention. The more information we have, the easier will be for our team to address it.