Webmail multiple errors

Hi,
I have installed the latest Onyx version, web pro edition.

I'm currently facing several issues with the webmail, all of them seems to be random and unrelated to each other.

• Roundcube (1.2.2):
  • Error 500 on login (only for certain users, and not always).
    Relevant log from /var/log/plesk-roundcube/errors:
    
    Code:

    [29-Dec-2016 09:18:20 UTC] PHP Fatal error:  Uncaught exception 'Exception' with message 'DateTime::__construct(): It is not safe to rely on the system's...

Webmail multiple errors