Downloading add-ons from Thunderbird hangs (91.10 on Mac)
Thunderbird 91.10.0 on MacOS 12.4. In Tbird, after going to Tools: Add-Ons and Themes, searching for "import" I see ImportExportTools NG. I cllick on the + add to Thunderbird button, but progress bar hangs (addons.thunderbird.net downloading and verifying add-on...). Screenshot below.
I've also tried downloading the .xpi file (11.1) and manually adding it (install add-on from file) and that doesn't work either. Also tried downloading two other add-ons, and get same problem: progress bar hangs on "downloading and verifying," progress bar doesn't move at all.
I definitely have Internet access. I've tried quitting and restarting Thunderbird app. Any suggestions?