Warning : mysqli_stmt_close() expects parameter 1 to be mysqli_stmt, boolean given in /srv/disk1/2648096/www/example.com/login on line 86
The error means what it says, you supplied a boolean value instead of a mysqli_stmt object as the parameter to the mysqli_stmt_close() call.
Without having all the relevant code, there’s no way to determine what is causing the problem. Could be a typo/wrong variable name, a prepare() call that is failing w/o any error handing in your code, or even using mysqli_stmt_close() where it ins’t needed.
If you cannot determine what is causing the error, you will need to post all the relevant code.
However, if you switch to the much simpler php PDO extension, these type of errors will be reduced (the mysqli extension has an overly complicated programming interface, resulting in you, the programmer, needing to keep track of many more statements and variables in your code…)
It means your statement failed.
Post your code here, rather than a link to a third party.