It's important to keep your software up-to-date.Your Joomla 3.6.4 has been released in October 2016.
The most recent Joomla version is Joomla 3.9.19 (June 2020). In between those versions, whole bunch of issues (including some security issues) have been fixed. It's a waste of time to try fixing issues with outdated software. Those issues might have been fixed already in the current version.
Please update your extensions + Joomla to the most recent versions, and then test again. Make sure that you create a backup (files + database) before doing those updates, for example using Akeeba Backup.