Crystal Reports 2013 prompt edit is hanging

Hi All,

Crystal Reports 2013 was installed on the App Server. All reports were migrated from CR 2011.

Couple weeks later all the users started experiencing the same problem for all reports (one more time - all the users for all the reports):

Go to the report --> Schedule or change Default Settings --> Prompts --> Edit Values and the system is hanging and never returns back until your session is expired.

Application restart didn't help.

Please help if anyone had anything similar.

Thanks in advance.