I have an html file add-offer.html containing 3 forms. I collect the data from these forms with javascript and then fetch it with fetch() to the file add-offer.php. The php file contains validation of the data, which I then try to insert into a database table. There are also two more queries that need to be executed. The data is submitted and some of it is added to the database, but I get error messages 405 and 500 and the rest of the php file is not executed.

I checked whether there was an issue connecting with the database, which was not the case. All files that need to be used exist and I checked for typos in their names. I checked the names of the tables and columns I’m inserting information into – they are correct. I am also getting an error message for the POST method, so I tried to solve this issue by removing all the “method” and “action” properties from the forms themselves, because the combined data is fetched with “post” in the javascript fragment.