- Plesk 12.5 for Linux
- Plesk Onyx for Linux
The following error is shown for a WordPress installation while trying to "Check Security":
An error occurred while checking the administrator's username on the WordPress installation 'My CMS'
WordPress Toolkit shows instances as not synced and not manageable.
The following error can be found in
[2016-08-20 06:50:12] ERR [util_exec] proc_close() failed ['/opt/psa/admin/bin/wpmng' '--user=hub' '--php=/opt/plesk/php/7.0/bin/php' '--' '--path=/var/www/vhosts/example.com/httpdocs' 'core' 'info' '--format=json' '--check-updates=true'] with exit code 
PHP 7.0 is used for this domain.
It is a software issue with internal ID #PPPM-4846 . The fix will be included in future Plesk updates.
Change PHP version to 5.x
Update rmccue package for the plesk-wp-cli
Get and extract sources:
# wget https://github.com/rmccue/Requests/tarball/master -O - | tar xzv
Copy them to plesk-wp-cli:
# cp -R ./rmccue-Requests-fb5b517/* /usr/share/plesk-wp-cli/vendor/rmccue/requests/