Are you logging in from outside the US? Make sure you setup your language as US-English after logging in.
Here's the logged in header with Canada-English set. You will get an error if you try to post in the community. If you have anything other than US-English in the header you won't be able to use the community.
So switch to US-English WHILE YOU'RE LOGGED IN to your GoDaddy account. The URL will switch to www.godaddy.com and the language should be United States-English before you navigate over to www.godaddy.com/community to register a handle and begin interacting.
Trust this will be fixed eventually by the GoDaddy Community caretakers and stewards.
Thanks for writing this up, Alex! I'll fold it into a post for onboarding new community members.
Yup - got burned by that, but remembered that it had to be US - English when I noticed out of the corner of my eye that my language was set to UK- English.