Python Postgresql and Mongodb Unity Game user connection problem

I have unity3d game that required connection to Postgresql and Mongodb server to play online.
After install all frontend and backend server and both server running I get following error when trying to play game with username and password:

Database exception while getting session: TypeError('Secret key missing for non-string Cookie.',); ignored.
auth for user test1 with hash 098f6bcd4621d373cade4e832627b4f6 (got 098f6bcd4621 d373cade4e832627b4f6)
test1 authenticating with client version 0.3.0.4...
Traceback (most recent call last):
File "/usr/local/lib/python3.6/dist-packages/bottle.py", line 862, in _handle
return route.call(**args)
File "/usr/local/lib/python3.6/dist-packages/bottle.py", line 1729, in wrapper
rv = callback(*a, **ka)
File "/usr/local/lib/python3.6/dist-packages/bottle_sqlalchemy.py", line 155, in wrapper
rv = callback(*args, **kwargs)
File "/home/Latestfiles/frontend_server/sessions.py", line 72, in wrapper
return func(sess, user, *a, **k)
File "/home/Latestfiles/frontend_server/metrics.py", line 24, in wrapper
d = func( *a, **k )
File "frontend.py", line 943, in login
d = finalizeLogin( db, session, user, clientversion, clientplatform, screenN ame=user.username)
File "frontend.py", line 442, in finalizeLogin
session.user_id = user.id
AttributeError: 'NoneType' object has no attribute 'user_id'
"POST /login HTTP/1.1" 500 885 0.149311

The error is frontend which connects to postgresql server. So I am pretty sure it has something to do with postgresql or python coding.

Please bid if you understand the error above and know python, mongodb, postgresql.
All you need to do is check the error and fix the problem so I can login in my unity3d game.