Hi,
can you enable wp_debug in your wp-config.php to see the error?
Hope this helps.
Fatal error: Uncaught Error: Call to undefined function mb_convert_encoding() in /home/xxxxxx/public_html/prelim/wp-content/plugins/wp-seopress/inc/functions/options-social.php:605 Stack trace: #0 /home/xxxxxx/public_html/prelim/wp-content/plugins/wp-seopress/inc/functions/options-social.php(636): seopress_thumbnail_in_content() #1 /home/xxxxx/public_html/prelim/wp-includes/class-wp-hook.php(286): seopress_social_fb_img_hook('') #2 /home/xxxxxx/public_html/prelim/wp-includes/class-wp-hook.php(310): WP_Hook->apply_filters(NULL, Array) #3 /home/xxxxxx/public_html/prelim/wp-includes/plugin.php(453): WP_Hook->do_action(Array) #4 /home/xxxxxx/public_html/prelim/wp-includes/general-template.php(2614): do_action('wp_head') #5 /home/xxxxxx/public_html/prelim/wp-content/themes/generatepress/header.php(18): wp_head() #6 /home/xxxxxx/public_html/prelim/wp-includes/template.php(688): require_once('/home/xxxxx/...') #7 /home/xxxxxxx/public_html/prelim/wp-includes/template.php(647): load_template('/home/xxxxxx7/.. in /home/xxxxxx/public_html/prelim/wp-content/plugins/wp-seopress/inc/functions/options-social.php on line 605
What PHP version do you use?
PHP 5.4 is the minimum required.
RESOLVED
I looked further into this issue after another plugin I was testing caused a white screen. I think the issue is that this particular server does not have an optimal php configuration. I copied the site to another server and your plugin works fine.
I guess mb_convert_encoding module was missing in your PHP configuration.
Thank you for your feedback.