Problem with receiving mail via Outlook on a terminal server, where to dig?

Question

Outlook

Good afternoon.
The situation is as follows: the host hypervisor esxi 5.5 has 3 VMs running on it: 2 terminals and a DC.
One of the terminals has a problem receiving mail. We use Outlook 2013, mail hosting is on Yandex, we use the IMAP protocol.
There is a situation in the mail client when "Send and receive" nothing falls into the mailbox, you have to open and close outlook and after that letters will start to arrive for a short period. If you look through any browser, then everything is in order, all letters are visible and sent
. Logic Windows once noticed about a month ago that the warning was also the source of tcp, but somehow didn't pay close attention
.
Windows Server 2012r2 (Version 6.3 Build 9600)
Any attempts to resolve this issue would be much appreciated.