It is not working for me either. I tried to reinstall as well.
I have been on e os for the past 1.5 years and it was working fine until now. I am incapacitated by it and had to install the app on an old standard android phone.
I contacted the customer service and was told custom ROMs are not supported and I should use normal android installation.
I am on unofficial build, I wonder whether the official flavour with locked bootloader works.
A bank switch may be needed but this is a business account and it is a bit complicated.
It looks like Monzo never had any issues with compatibility…