background not loading in certificate (Exclude media from jetpack photon )

Note that wplms uses Html2canvas script to take the screenshot of the generated certificate .
It does not supports background image from another source .Make sure that your image is hosted on the same host as you site is .
It would be better if it is uploaded in media library and  you added the image from it in your certificate .

IF you are using jetpack photon addon then the certificate image may not load due to it replaces the url  from cdn .
so to exclude only this image please try adding the following code in your wplms-customizer.php in the end before ” ?> ” in wplms customizer plugin :

add_filter( 'jetpack_photon_skip_image', 'my_photon_exception', 10, 3 );
function my_photon_exception( $skip, $src ) {
        if ( $src == 'YOUR_IMAGE_URL' ) {
                return true;
        }
        return $skip;
}