I am facing a problem in my Windows Server 2016 VMs. I have 3 terminal servers: T1, T2, T3 - all on different Hyper-V hosts. I have 2 Domain Controllers: AD1 and AD2. AD1 is the primary one. In the DNS settings of all 3, we have the IPs of AD1 and AD2.
Recently, randomly, one or two terminals start showing a problem where we are unable to browse the internet. Firefox or Chrome or Edge, nothing works. Even API calls do not work. But pinging local IPs, 1.1.1.1, google.com and nslookup also works. After some time of this, Firefox crashes. The problem is not isolated to T1 or T2 or T3. It occurs randomly in one of them or two or all three.
We have had cases where the RDP also stops working. We have had to go to the Hyper-V manager, access the VM, and resolve it. Sometimes, just restarting the Remote Desktop Services works. Doing that also solves the browsing issue. When that doesn't work, we restart the Network Adapters. That solves it for some time and the issue occurs again later.
We have also rebuilt fresh Domain Controllers from scratch but the issue remains. Please suggest what I should do to solve or find the cause for this. No updates have been done to Windows.
Information: All 3 terminals are Windows Server 2016. The VMs are on 3 separate hosts, all Supermicro. The RAM for each terminal is around 200GB. The processors are Intel Xeon series. Each terminal has 36-40 processors assigned. Approx. 30 users work on each terminal simultaneously. The primary applications are: SAP Business One (ERP), Firefox, and Excel (for loading data from the database via ODBC).