Steps to reproduce the issue

When trying to install extensions via the Extensions > Manage > install I receive the warning
"No installation plugin has been enabled. At least one must be enabled to be able to use the installer. Go to the Plugin Manager to enable the plugins."

I followed some of the other posts and they suggested going to the Discover tab to discover the uninstalled plugins needed but that also came up with nothing found. I have also tried to manually download the zip file to my server and install the installation folder on the server side. That didn't work either.

Expected result

Joomla to allow the installation of plugins

Actual result

Warning

No installation plugin has been enabled. At least one must be enabled to be able to use the installer. Go to the Plugin Manager to enable the plugins.

System information (as much as possible)

PHP 7, Joomla 3.6.5, mysql 5

Additional comments