i was resently at factions and when the serverrestart came and i try to join again this happend i was not able to join the server for 15 mins
That's lag. It happens sometimes... You get kicked or timed out but it takes a while for the server to 'understand' that you're not online anymore.
To fix this restart your router at your house, this usually fixes it for me. If it does not fix it for you then I suggest you to wait for server restart it automatically kicks everyone so if your player is still online it will kick it. Usually this bug only lasts for like five seconds and then it will automatically allow you to rejoin the server, But it's not seem to be the case here.