We are just sorting out the SSO for the new version of Vanilla Forums; until this is sorted out, you can’t log in - and so can’t post. Hopefully we should get this sorted in the next day.
As you may have noticed, things are afoot - switching to a new forum & better integrated login. All the content has been moved too.
Hopefully back to normal shortly.
Thanks @ahoughton ! The downtime was my fault… but thought taking the opportunity to switch to a newer forum software package was worth it 
Just fixed an issue with email login. If you’ve been having issues, try again now.