finally looked into why, for the past 2 weeks, my WPEX wouldn't load...
the client-main.txt states...
[Error] [wpex] An exception was thrown when trying to load assembly:
System.IO.FileNotFoundException: Could not load file or assembly 'netstandard, Version=2.0.0.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51' or one of its dependencies. The system cannot find the file specified.
File name: 'netstandard, Version=2.0.0.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51'
...so, it seems that wpex is trying to find netstandard.dll, which doesn't seem to be included with wpex.