This seems to be common at the moment.
I'm having very similar issues with my own server, though i also get crashlogs showing out of memory errors with the server crashing anywhere after between 5 minutes and 3 hours uptime at which point it shows it's still there, gives a timeout when trying to connect and trying to restart leads to it getting stuck in restarting for 20 minutes and having to force stop to get it to start again.
I did look into the crash logs and it is the same for me. Out of memory, then it has a problem shutting down properly and still shows up in the server lists. Then it is having some trouble restarting. So I believe we are having the same issue. I think today was the longest up time that I had according to my friend who was on it most of the day before it died recently.