This was resolved with a reinstall of the SDK Manager Installer. Admin feel free to delete this; I can’t seem to. Thanks.
Thanks for the update, good to know it’s resolved.
I faced this same issue.
My solution: logout and then login again. There will be a login action involving a step which goes to the browser, you login there, and then are routed back to the SDK manager. This was not obvious to me, but after this, I could download files.