The type initializer for 'AuthenticationServ.Authentication' threw an exception.

I had this issue before as well but I couldn't remember what I did at that time to fix this issue.
Anyway, I ended up spending hours trying to fix this again.

This is not something a good developer should be doing.
A good develope should always take a note of the issue and remember the fix he did for it.

N'way the fix was simple, it was caused since we were missing log4net.config file in the bin folder.