net::ERR_HTTP2_PROTOCOL_ERROR

Hello, I wrote simple php backend code when I finished PHP for beginners.

I wanted to upload it on the server and use it as an API on vue.js, which I did on 000webhost. It's a very simple CRUD website where you can see, add and delete products.

My problem is this: I can get all data and display it on the front but whenever I try to do a DELETE or POST request I get this net::ERR_HTTP2_PROTOCOL_ERROR. In the local environment, everything is working fine.