Website not available, server up but unreachable
I have some websites hosted on a VPS. Some of my visitors (known visitors) are telling me the website is not available on their end. At the same time the website is working from my location, so the server is not down, nor the network. I've got access to some computers using TeamViewer and it seems the websites are really unaccessible from time to time (for a few hours). I tried to traceroute the server and there are problems on the route, the connection is lost. The problem is this happens to multiple visitors from different locations.
What should I do? Thank you very much!