The Plugin Reposioriry interface is unavailable for me and I need to grab a plugin to update my firmware. Cura isn't letting me do it either because, as it, says, the connection isn't set up for it, although I've attempted several different connections.
What did you already try to solve it?
Have you tried running in safe mode?
Did running in safe mode solve the problem?
You can download this in OctoPrint's System Information dialog ... no bundle, no support!)
Additional information about your setup
OctoPrint version, OctoPi version, Ancubic Mega S printer, Chrome browser, OSX, nothing fancy**