Ah! It's just clicked in my head what has happened.
You said in your OP you had ceased the line. So AA closed your account and gave Openreach a Cease order
, which on ADSLx so probably also on FTTC takes a while to be actioned. It just has been.
That would explain sync but no authentication.
My broadband basic info/help site - www.robertos.me.uk.
Domains, site and mail hosting - Tsohost
Connection - AAISP Home::1 80/20. 200GB. Sync 01/10/18 - 72382/13812Kbps @ 600m. BQMs - IPv4
If you never think of anything off the wall, you'll never think of anything original.