INSTALLATION OF PLUGIN FAILED. WORKAROUNDS NOT WORKING FOR UPFRONT/BUILDER

Hi,

WPMUDEV Dashboard is not allowing installation of plugins after initially working okay on a clean WP Multisite Install. The problem is very similar to one in this ticket: https://premium.wpmudev.org/forums/topic/installation-of-plugin-failed-most-likely-reason-for-this-are-wrong-folder-permissions. However the suggested remedies from that thread are not working. I have loaded Defender directly from cPanel and got it working okay, but my main focus is Upfront/Builder and it will not install properly no matter what I do!

The error messages upon trying to install a plugin through the Dashboard run along the lines of "Installation of XXXX failed. Most likely reason for this are wrong folder permissions of your wp-contents folder".

The site is a clean install with no other plugins. Permissions on wp-content folder are set to 755.

I have tried deleting WPMUDEV Dashboard and reinstalling manually but that did not help the problem either.

Thanks for your help!