Lately I went into an issue where users recieved a dialog box in outlook saying, there is a problem with the security certificate;
The customer is running on Exchange Server 2016 and is using a Kemp Loadbalancer.
This MS article;
states that there is a problem with the security channel
Finnaly I found this article on F5 https://support.f5.com/csp/article/K10433354 and I decided to remove all normal DH Cipher suites from the Kemp Loadbalancer, so only the following suites are enabled;