Synchronizing folder Error

Hello all,
Just recently started using EM Client over Outlook and I really like it except for one really annoying bug. Every couple of minutes I get a popup error:

Stating that a synchronizing folder error occurred. Do note that I have a university email and there are 300K+ contacts in my directory/ folder. If I attempt to repair the folder the entire client crashes.

Hopefully there is a fix, because I really like this client but will of course have no option but to go back to outlook if this isn’t resolvable.