A little more information might help.
What sign in process? Do you mean opening RoboHelp? Do you mean trying to activate it?
RoboHelp HTML? What version?
What operating system?
Have you tried rebooting?
Did you install with Admin rights?
See www.grainge.org for RoboHelp and Authoring tips
I installed RoboHelp 10.
The sign in activation process hangs like it can't connect to the authentication server.
OS Windows 7
Yes I tried rebooting.
I installed with an activation key.
I don't have Windows admin rights - but that has not been an issue in the past.
I'm coming around to thinking this might be a connection problem at our end.