What is the error? Looks like it was removed by the editor here.
The error is : AH01071: Got error ‘PHP message: PHP Warning: Cannot modify header information – headers already sent by (output started at /var/www/vhosts/…/nav-desktop.php:1) in /var/www/vhosts/…/kb/wp-content/plugins/wp-super-cache/wp-cache-phase2.php on line 1197\n’
It seems similar issue as “WP Super Cache and PHP 7?”. It isn’t related to WPSC plugin and it could be an issue with other plugins (sitemaps,feeds for example).
It’s most likely that file nav-desktop.php is saved with a Byte order mark (BOM) or contains empty space before an opening <?php
tag.
More details – How do I solve the Headers already sent warning problem.