@robert with the help of a programmer at my hosting, after adding some debug code in file.php (wp-admin/include), there is some info in the debug log that _could_ help you solve this:
[17-Sep-2018 13:25:03 UTC] Starting edit check
[17-Sep-2018 13:25:03 UTC] Body:
[17-Sep-2018 13:25:03 UTC]
[17-Sep-2018 13:25:03 UTC] Connection failed
[17-Sep-2018 13:25:03 UTC] WP_Error::__set_state(array(
'errors' =>
array (
'http_request_failed' =>
array (
0 => 'cURL error 28: Operation timed out after 100002 milliseconds with 0 bytes received',
),
),
'error_data' =>
array (
),
))
Thank you Anonymous20,
Unfortunately the debug code says nothing new. The issue is general issue. All plugins who call session_start() function cannot be edited by WordPress editor, because the new version of WordPress editor tries to execute code to check if it doesn't returns any error. Other editors works fine, they don't try to execute the edited code. We'll check this and try remove session functions in dashboard.
Please try to do this small change in core file. We'll update it in next release.
Open /wp-content/plugins/wpforo/wpf-includes/class-notices.php file.
Find this line:
if(!wpforo_is_session_started()) session_start();
Change to this:
if( !wpforo_is_session_started() && !is_admin() ) session_start();
It took care of my issue described in this thread as well. Thank you.