This may be being caused by two factors: either a high amount of already online servers (Minehut has a 3450 maximum server limit; there are live statistics which you can moniter here: https://minehut.com/). However, your issue could also be coming from corrupted server files. In order to fix any files which may be delaying/stopping your server, go into the Danger Zone on your Minehut control panel and select Repair Files, then stop and start your server. Additionally, you want to be sure that your server is fully online before joining it, otherwise, you will be kicked.