You’ll want to use mysqli_errno and mysqli_error, since you’re using mysqli functions to connect to the database.
And you should really learn how to use them if you are going to develop your own software.
There are numerous guides online that can teach you how to use mysqli functions properly. Please follow those guides so you can have proper error handling.
Does it say sql308.epizy.com in the control panel? If so, then yes. If not, then no.
Also: please just try to grab the error message. You can speculate what the error is and throw stuff at the wall hoping it is the actual issue, or you can put in a bit of effort now and you’ll know exactly what the error is, have a great start on how to fix it, and have learned something useful to help you if you ever have database troubles again.