Hi @epsilonadmin
Thanks for your support.
First the license we have is Active.
Second, this web is published so this is not in local machine
Third, since yesterday we have continue publishing documents and some of them are right indexed and others not.
In the case that the document is not indexed, wordpress does not show its preview.
If we try to reindex any of the documents not indexed we can see in console browser there are a 500 error code.
The lines of error log for a reindex attempt are:
[Tue Jan 19 09:25:59.628193 2021] [fcgid:warn] [pid 6233:tid 140198847399680] (32)Broken pipe: [client 185.222.150.225:54502] mod_fcgid: ap_pass_brigade failed in handle_request_ipc function, referer: https://sitte.advanto.net/wp-admin/post.php?post=307&action=edit
[Tue Jan 19 09:26:18.738949 2021] [fcgid:warn] [pid 29596:tid 140198771865344] [client 185.222.150.225:54924] mod_fcgid: stderr: PHP Fatal error: Uncaught Error: Cannot use object of type WP_Error as array in /var/www/vhosts/advanto.net/sitte.advanto.net/wp-content/plugins/fulltext-search-pro/extractors/textmillio.php:121, referer: https://sitte.advanto.net/wp-admin/post.php?post=307&action=edit
[Tue Jan 19 09:26:18.738988 2021] [fcgid:warn] [pid 29596:tid 140198771865344] [client 185.222.150.225:54924] mod_fcgid: stderr: Stack trace:, referer: https://sitte.advanto.net/wp-admin/post.php?post=307&action=edit
[Tue Jan 19 09:26:18.738991 2021] [fcgid:warn] [pid 29596:tid 140198771865344] [client 185.222.150.225:54924] mod_fcgid: stderr: #0 /var/www/vhosts/advanto.net/sitte.advanto.net/wp-content/plugins/fulltext-search-pro/includes/wpfts_core.php(1012): WPFTS_Extract_TextMill('/var/www/vhosts...', 'application/pdf'), referer: https://sitte.advanto.net/wp-admin/post.php?post=307&action=edit
Hope this information help to understand what is the issue.