aaPanel_Kern Yes I'm using deploy. Yes everything is normal, and yes you can add a database.
There was a previous version of dev.domainname.co.uk on the server which was deleted years ago. It appears to me that when you delete sites something is left over which prevents their recreation.
For example I was able to create new.domainname.co.uk perfectly.
I've run threads on this issue going back to 2021 and it's still a problem.
Also error messages such as 'deployment failed' aren't helpful, and error messages which disappear in less than a second are equally unhelpful