Serial com ports shut down using Rapidport/4 modem

I’m using AnywhereUSB and Rapidport/4 Modem with on Wondows 2016 server. The FAX software is Zeta fax from Equisys. It would work hour or so and then a random serial comport will shutdown, after that the Zeta Fax server will shutdown since it can no longer write to that port. I’m interested to know if any one encountered similar issue and what was the solution or any troubleshooting idea would great.

Modem: Rapidport/4
Serial Number: W81293603

AnyWhereUSB: AnywhereUSB/5
Serial no: SE85142314

Computer OS: Windows Server 2016 Standard
This server is running on VMware host

If you look on the label on the bottom of this AnywhereUSB/5, what does it show for its re-order part number?