[Evolution] Missing Oauth2 secreat

[Japhering <japhering gmail com>]

Somewhere I've missed a step .. .

I think I have Evolution 3.28.1-2  (LinuxMint 19) configured but upon
attempt to connect to gmail I get hit with the following 
error:

   Failed to connect account <account name>.
   The reported error was "Failed to authenticate:  OAuth2 secret not
   found"

Any hints on what I screwed up or pointers into documentation that I
have yet to find ?

Mike