There is a review history for the question where it can be seen that it has been closed several hours after the OP fixed the issue.
Why people kept voting if they could see that the reason is not applicable anymore?
I can understand the votes to close that were cast before the code was added to the question. As for the code-not-working votes, I am not sure about those. It is possible that there is an issue with the code, but I can't see one (PHP is not a language I know very well). There are no comments though indicating what the problem is though.
Given that, I have voted to reopen the post (and as a mod, it is now open again).
Hope you get good answers.
Three of the votes were because there was not code in the question. The users probably didn't come back to check if the question was improved and withdraw their close votes. And so made it easier to close for a different reason.
Two people closed with the code not implemented or not working as intended reason. This may be because the wording on the question is a bit complicated:
This is a form that I want to use to enter users into a database. I used MySQLi with prepared statements. I want to make sure that I sanitized my data well.
At first I was confused if the code was working or not by that description. But they're just saying what they're using and what they hope to achieve out of a code review. And so because there was three close votes already it made it easier for this to be closed due to what I think is a misunderstanding.
I feel it's on-topic, as described above, and so I have started a vote to re-open.
It sometimes happens that people don't read the question carefully enough to make a good judgment whether it should be still closed or left open and press the close button prematurely - admittedly, I did it a couple of times too and then regretted it.
If that was the case and a question gets closed anyway, you can always vote to reopen it and maybe add a comment that the issues has been fixed. It'll get to another queue and we'll reopen it again.