Error message

Fatal error: Uncaught PHPMailer\PHPMailer\Exception: Invalid address: (From): ask@localhost in /www/wwwroot/howchinese/wp-includes/PHPMailer/PHPMailer.php:1300 Stack trace: #0 /www/wwwroot/howchinese/wp-content/plugins/easy-wp-smtp/easy-wp-smtp.php(173): PHPMailer\PHPMailer\PHPMailer->setFrom() #1 /www/wwwroot/howchinese/wp-includes/class-wp-hook.php(307): EasyWPSMTP->init_smtp() #2 /www/wwwroot/howchinese/wp-includes/class-wp-hook.php(331): WP_Hook->apply_filters() #3 /www/wwwroot/howchinese/wp-includes/plugin.php(524): WP_Hook->do_action() #4 /www/wwwroot/howchinese/wp-includes/pluggable.php(542): do_action_ref_array() #5 /www/wwwroot/howchinese/wp-includes/pluggable.php(2154): wp_mail() #6 /www/wwwroot/howchinese/wp-includes/user.php(3418): wp_new_user_notification() #7 /www/wwwroot/howchinese/wp-includes/class-wp-hook.php(307): wp_send_new_user_notifications() #8 /www/wwwroot/howchinese/wp-includes/class-wp-hook.php(331): WP_Hook->apply_filters() #9 /www/wwwroot/howchinese/wp-includes/plugin.php(476): WP_Hook->do_action() #10 /www/wwwroot/howchinese/wp-includes/user.php(3398): do_action() #11 /www/wwwroot/howchinese/wp-login.php(1047): register_new_user() #12 {main} thrown in /www/wwwroot/howchinese/wp-includes/PHPMailer/PHPMailer.php on line 1300 There has been a critical error on this website. Please check your site admin email inbox for instructions.

Solution

This is the bug of the SMTP mailer plugin. It's better to find an alternative plugin.