Php download file server

6 days ago Opening website leads to the index.php being downloaded instead of being opened. Cannot login into WordPress because the wp-login.php file is downloaded instead. (Optional symptom) Server: Apache X-Powered-By: 

Hi,. Do you mean from other server to your server?, or from server to your computer?

PHP can detect buggy IIS server software when you open the stream using the https:// wrapper and will suppress the warning.

I guess you haven't taken a look at the file that is served for downloading, if so you would have seen this: Send AJAX Request and download file All rights reserved