Any of the following symptoms may occur on a QlikView Server when trying to assing a CAL:
Cannot assign new CALs.
No CALs listed as available and all previously assigned CAL information is missing
No settings can be edited on the license tab (settings reverts back when pressing Apply)
This might be caused by either out of sync or corrupted PGO files.
Resolution
Stop the QlikView server service.
Remove (make sure to backup the files!) the PGO and DAT files found in the QlikView Server folder: %ProgramData%\Qliktech\QlikView Server\
Make sure to do this on all QlikView Servers if running a cluster.
Remove (again, make sure to backup the files!) the PGO files found in the Documents folder (shared folder if running a cluster).
Restart the QlikView Server service.
Make sure all the folders get populated with new files and verify in the QlikView Management Console that all the above mentioned functionality is restored.