The error message in the title is covered by https://kb.pulsesecure.net/articles/Pulse_Secure_Article/KB2388 , you must have hit the soft limit as you could continue to connect.
A Role is part of the configuration on the PCS that Pulse/NC connect to and is defined by the administrator, more information is in the Admin Guide starting at https://docs.pulsesecure.net/WebHelp/PCS/8.3R1/Home.htm#PCS/PCS_AdminGuide_8.3/User_Roles_Overview.h...
The Event log is a log file on the PCS availble to the administrator that records any notable events which would include the license count being reached or failures to contact an authentication server, for example.
The Pulse client has a debug log that records messages from only the Pulse client and its components.
As there are many different configuration options available it is usually best to contact your administrator if you have any issues and they can contact us explaining what the user problem is along with what they have configured if they are not able to resolve the problem - without knowing what is configured on the PCS we can only guess and make general suggestions about reported problems as the configuration controls what the expected behaviour is.