22nd of May 2025 - Service Announcement New server certificate for Exchange-Cluster

Update: The problem has been solved, the error message should no longer appear.
If you have any questions, please do not hesitate to contact us.

The Exchange server certificate has been updated to comply with current security guidelines.

With older devices or operating systems that are not up-to-date or supported, a certificate warning may appear when trying to connect to the Exchange server.
In most cases, it should be sufficient to install the root certificate on your device. 
Please look for suitable instructions for your affected device yourself, as there are no universal instructions available.

You can download the required root certificate “HARICA Client RSA Root CA 2021, 2021” here:

https://repo.harica.gr/rep_dyn.php