If this was after midnight, there's often maintenance going on overnight, @regfiet3.
Keep an eye on the service status dashboard.
https://community.talktalk.co.uk/t5/Service-Status-Dashboard/bd-p/service
Was this your billing account or your webmail?
Gliwmaeden2, a fellow customer.
From the 29th of March our TalkTalk Community will move to peer-to-peer support and the TalkTalk team will no longer be here to support with queries. Don’t worry we still have plenty of ways to reach out if you need to speak to TalkTalk directly. For more details check out the link in the post at the top of any forum message board.
