Nabble issues

Hi,

Since a little while it seems to be impossible to either post or reply 
to messages in the help and maintainers mailing lists through Nabble.
I'm not subscribed to any of the Octave mailing lists (to cut down on 
e-mail volumes) and Nabble was AFAIK the only way to easily respond to 
e.g. requests for help.
These days, when trying to reply or enter a new post, I'm taken to a 
page where I can plea for permission (see attached pic), even though I'm 
logged in (see attached pic).

In addition, Nabble's future seems to be uncertain, see:
http://support.nabble.com/The-Future-of-Nabble-td7605923.html

Is there any other fairly convenient way to respond to mailing list 
postings, other than e.g., copying messages by hand into a new email as 
quote and morphing them into a sort of makeshift reply? (that, as a 
consequence, isn't absorbed into the thread)

While I wouldn't want to do away with mailing lists IMO the concept is 
becoming more and more outdated. I think a forum would be a better way 
to communicate about help requests or maintenance issues. No need to 
subscribe, maybe only a filter to keep bots out.
Are there viable and really free (+ free of privacy-issues) forum-like 
alternatives for Nabble?

Thanks

Philip