Hi Michael,
I don't think that's supported currently. This excerpt is from TechNet Article
"Internet Message Access Protocol (IMAP) email servers are currently not supported with server-side synchronization or the Email Router"
Link: https://technet.microsoft.com/en-us/library/dn832099.aspx
Hope it helps!
Regards, Abhishek Bakshi If you find this post helpful then please Vote as Helpful and Mark As Answer. Check my blog on https://mydynamicscrmblog.wordpress.com/