sesman and xrdp: xrdp_mm_process_login_response: login failed

When trying to login to an xrdp session I got the following error, running Android Debian Kit:
xrdp_mm_process_login_response: login failed

I tried any username and password, none worked.

Then I found this page:
http://linuxtoolkit.blogspot.se/2013/03/xrdpmmprocessloginresponse-login-failed.html

The solution was to remove some files in the temporary directory, then restarting xrdp and sesman:

rm /tmp/.X11-unix/*
Restart xrdp and sesman (in Android Debian kit: xrdp-stop then xrdp-start)