XRDP disconnects immediately after correct credentials
Solution 1:
Based on your description of the problem, this could be due to the fact that you are already logged in into your Ubuntu and you are trying to use the same user account to make your remote desktop connection.
It's not possible (with xRDP software) to use the same user account and login at the same time on Ubuntu locally and perform a remote connection...
To assess if this could be the problem, please ensure that the user account will to perform the remote connection is not logged already on your Ubuntu machine....
Hope this help Till next time See ya
Solution 2:
For future reference, I had the same issue, and without diving too deep into why it was happening I simply installed another desktop environment (xfce4) and it worked fine. It seems to be a problem with GNOME.
To install:
sudo apt install xfce4
and then to switch to it:
sudo update-alternatives --config x-session-manager