New meter, sad CAD

Hey folks, hope you're all well!

My smart meter died in June, and finally this week I was able to get it replaced... which involved switching providers from E.On Next to Octopus due to E.On Next taking months to even notice there was a problem(!)

However, now my CAD won't join the new HAN.

Any ideas as to how to get it to connect?

I emailed support the other day; I am ridiculously aware of the fact that I'm impatient but just wanted to see if anyone on here had any suggestions :D