I have been having similar issues. I was able to connect around 23rd March and, having had several long chats with QB support I received 2 emails yesterday telling me my problem had been resolved - I did mange to connect both Online and Self-employed apps yesterday - but last night and today I keep getting connection issues again.

I', not convinced it's anything to do with the new government regulations because when I contacted First Direct open banking they said,

"This issue is caused by the fact that you can no longer log on to Online Banking with us using just a password. You now need to enter a log on code each time. Quickbooks will need to change their service to provide you with an open banking method of linking to first direct. To troubleshoot further, please contact them"

and, indeed, the security log in via QB seems slow and laborious ending up with that "try again later" message. 

I don't know whether to change bank of ditch QBs...

Has anyone resolved it yet?

Dermot