APE 2020.2.1 is down after failover

Question

As I see, 2020.2.1 HF2 is very unstable.
After failover, I got some plugin errors:

12/21/2020 5:58 PM Plugin "CLI Business Layer" failed to start on [APE01]. Please restart the Module Engine service on [SPBSWSAPE01].
12/21/2020 5:58 PM Plugin "Device Studio Business Layer" failed to start on [APE01]. Please restart the Module Engine service on [SPBSWSAPE01].
12/21/2020 5:58 PM Plugin "NPM Business Layer" failed to start on [APE01]. Please restart the Module Engine service on [SPBSWSAPE01].

Restart didn't fix this. All services were Up, but:

LAST DATABASE SYNC

37 minutes 45 seconds ago

Also had no data from APE-polled nodes.
So tried to perform a config.wizard and got a new error:

Orion Database configuration FAILEDServices configuration failed:
• Could not load file or assembly 'SolarWinds.Orion.Core.BusinessLayer, Version=2020.2.15300.12901, Culture=neutral, PublicKeyToken=null' or one of its dependencies. The system cannot find the file specified.

There are no errors like "Could not load file _" in BusinessLayerHost.log so dunno about which file it is.

Have no idea how to fix this, service is down and support is in no hurry.
Any thoughts?

omavel · Accepted Answer

Well, I don't know why, but my installation had no SolarWinds.Orion.Core.BusinessLayer.dll file in Orion directory. So I just copy it from my MPE server and successfully performed reconfiguration with wizard. Fortunately, service started well.

I know what you’re thinking - it's because of antivirus.
BUT. I have the latest release - 2020.2.1 HF1 and I made a clean install - not update. So this dll couldn't be recognized as trojan - we have fresh signatures. Moreover, I checked antivirus logs and there were no detections.

Mystery.