Trouble with Data Base

In my script, I send a POST request like this:

I have a file “upload.php” in the folder “htdocs”.

Thus, I check for the presence of a specific line in the Base, if it does not exist, add it.
The essence of the problem is that when I send, I get this answer

With other databases, this worked, I ask you to help find the problem.

The file is here.

What the answer should look like.

From where do you send Post request? If it’s not by Browser read this article: