Um, the idea of btinternet users only posting via the web interface is surely a non starter.
They can post messages to the group using whichever interface they like. It is only email commands (including messages to +owner) that are afflicted by synchronoss' error.
I have no statistics but I sense on the groups I moderate that probably 80% of users, including a LOT of btinternet users, only use email and most have never been anywhere near the web interface.
Whose web interface are you talking about? I'm not talking about using Groups.io's web interface, I'm saying those members need to send email commands using btinternet's webmail interface.
From what I've heard, it is only fossils like myself that cling to SMTP email clients like Thunderbird and Outlook Express - that most email users now use their service's webmail interface instead.
