[NSFW] ERROR – document.close(); – Error in Safari

I have found the solution for this problem!

When you are using document.open(), document.write() and document.close() you can rewrite a hole site, when it is loaded at the wrong time and exactly this happened here.

Therefore I searched the repo of the plugin and found the file where they are using the document.close() you can find it here: https://github.com/froger-me/wp-remote-users-sync/blob/master/inc/templates/redirect-processing-script.php

SOLUTION:
In case you want to solve this problem. Go to the plugin file on your server, in the file “redirect-processing-script.php” and just comment out the two lines

document.open();
document.write(‘<?php echo $output; // @codingStandardsIgnoreLine ?>’);

It is important to let the “document.close();” persistent, because otherwise your site will be visible, but interaction is disabled.

Many thanks to me, finding this out within 2 month of work