My server tends to kick everyone and go ??? ping for about half an hour when there are more than 25 players on, then they come back on about half an hour later. If they are off for longer then it is best sending a ticket to funcom. Go to :
https://funcom.zendesk.com/
Select “Submit a report”, Request type - Select “Offical server peformance”. Fill in the info, in description just put that its offline with ??? ping. Sometimes this isnt necessary as it comes back on after about half an hour.