Our Twitter Single Sign On integration (used to enable signing into the Forum with your Twitter login) was suspended yesterday. We believe (although not 100% sure) that this is down to the changes to the Twitter API access that have been introduced.
For the moment I’ve removed the Twitter SSO, but we could investigate re-instigating if people are using this method of sign on. Feel free to reply to this thread if you already use the Twitter SSO and need us to investigate restoring access.