Running 9.4.3 but still having this issue here. (Couchpotato 3.0.1)

java.lang.illegalstateexception: Expected BEGIN_OBJECT but was STRING at line 2 column 1 path $
Super late to the game, I know; but I just figured out the fix (for my situation). I have a CouchPotato instance behind an Apache SSL reverse proxy, so I had to add an extra directory after the port number (in my case, it was port: "443/movies").

Anything between your ".com" and "/login/?next=%2F" should be added as part of the port (See screencap).

YMMV, but if you haven't figured it out already, give it a go..