Update 1 October 2020 16:20:
The problems with sending and receiving e-mail have largely been solved.
* Using e-mail via Outlook (on PC or app on cell phone) is fully available again. There is no longer any delay in sending or receiving e-mail, including sending to distribution groups;
* The Outlook Web Access is accessible again for almost all users. The supplier indicates that they are currently solving problems for some users who are still experiencing problems.

Update 1 October 2020 11:11:
* It is not possible to use email in Outlook Web Access.
* It is possible to use email via Outlook app on PC or mobile. (Mail send & receive works with possible small delay)
* Sending mails via distribution groups has a delaying effect (15 minutes or longer depending on the size of the distribution group)

Malfunction 1 October 2020 10:04:
You can currently not or only to a limited extent use the Cloud solismail.
Oultook.office.com is not available and email sent is delayed.