Hi,
Please try the following:
1) Update to latest WordPress
2) Disable all plugins
Check your site and if everything is working fine then enable plugins one by one to find out the conflicting plugin.
About the versions: Free version and Pro version have different version numbers. Current latest Pro version is v2.8.
To upgrade refer this guide: https://themonic.com/forums/topic/how-to-upgrade-iconic-one-pro-responsive-theme-to-the-latest-version/
If there is still issue after upgrade, send login information to [email protected] with link to this thread and we will check it out.
Update: This issue was caused by outdated plugin WP Hide Post, resolved via email.