Cannot login to my user?

[Thomas Anderson <thomas.anderson@little-beak.com>]

Hello Friends,

I have Debian 9, I know I need to upgrade my dist, will do that tonight 
or tomorrow =)

Last week, I made a new user say "Sally."

Previously, for years, my main user "Bob" was running perfectly with a 
gnome desktop.

Recently, I realized, I cannot login to Bob anymore?!?

The login screen loads as expect, i type in my credentials for Bob, the 
screen goes black, then I end

up at the login screen again?!?

Sally can login. Sally happens to have a Xfce.

I checked that there were no root owned files on Bob. There are none, 
since I read that could be a cause.

Is there a log file I can check for login errors?

Thanks