The indicator has nothing to do with the repository, it’s basically showing the memory usage.
For how long have you been waiting? Giving it some minutes is probably not a bad idea.
Next I would suggest to try the ominous “clean” parameter, about which you can read here. It’s a magic potion for fixing all kind of KNIME plugin hiccups.
Does the KNIME log show any error messages?
If all this does not help, I you can re-install KNIME. You’re running on a Mac, so remove the current version from your “Applications” directory, open the downloaded DMG and drag a fresh copy to Applications. Your “workspace” which contains your workflows will be preserved, and you can select it upon next launch of the freshly installed copy.
Hope that helps!