I got the 403 unauthorized message when trying to upgrade to 0.11.1 from 0.10.15. I got an idea when reading the SETUP / HOW TO INSTALL LICENSED EDITION on Chocolatey.org’s site. The trick is to upgrade chocolatey.extension and not chocolatey directly. It will upgrade chocolatey as a dependency for the extension.
Enjoy the rest of your day and hit the like if this helped you!