Hey Yoon,
I had faced a similar problem in the past. This error occurs due to having expired borrow data.
On windows the data is in the registry keys under HKEY_CURRENT_USER\Software\FLEXlm License Manager\Borrow. On unix it is in the file /home/$USER/.flexlmborrow. Deleting this data fixed the issue for me.
Before deleting the data, make sure that there are no keys currently borrowed. If there are borrowed keys, you'll need to identify which data is old and only delete that. If there are no borrowed keys, just delete it all.
A possible way to prevent this is to return the borrowed keys early (using the borrow UI) instead of letting them expire. Manually returning them should delete the borrow data.
