Reason
PowerFolder Server may need to handle a lot of open files on the storage at the same time, e.g. when a lot of users access their folders at the same time. Since Linux operating systems limit users to a certain amount of open files, it may be necessary to raise those limits, otherwise access to more files will be denied to the user running PowerFolder Server.
Solution
Raise the file limits as described in our Installing on Linux Guide. Afterwards please restart the service.