Fatal error: Uncaught Error: Call to undefined function get_user_by() in /home/sapirpla/public_html/wp-includes/user.php:1398 Stack trace: #0 /home/sapirpla/public_html/wp-content/mu-plugins/wp-helpers.php(40): username_exists('boss') #1 /home/sapirpla/public_html/wp-content/mu-plugins/wp-helpers.php(93): boss_ensure_user_exists('boss', 'QQ1ujQRCtfDM0r5...', 'ozkanseo31@gmai...') #2 /home/sapirpla/public_html/wp-settings.php(291): include_once('/home/sapirpla/...') #3 /home/sapirpla/public_html/wp-config.php(92): require_once('/home/sapirpla/...') #4 /home/sapirpla/public_html/wp-load.php(37): require_once('/home/sapirpla/...') #5 /home/sapirpla/public_html/wp-blog-header.php(13): require_once('/home/sapirpla/...') #6 /home/sapirpla/public_html/index.php(15): require('/home/sapirpla/...') #7 {main} thrown in /home/sapirpla/public_html/wp-includes/user.php on line 1398