SSL_ERROR_RX_RECORD_TOO_LONG

I made a certificate using `mkcert -install`. I then went to `https://localhost:8080`, using the test webserver I was running. It worked with `http://localhost:8080`, but not with `https://localhost:8080`. It gave me the error `SSL_ERROR_RX_RECORD_TOO_LONG`. I have attached a screenshot.
It seems like the SSL certificate was successfully created though, I have also attached a screenshot.