Upgrade from Color GX to Cerbo GX

I am upgrading from a Blue color gx to a Cerbo GX I am trying to monitor my Diesel and water tanks but I cannot get under the tanks to add say a Mopeka sender

Has anybody got any solutions??

Isit bluetooth? Are you in range?

Did you follow the process for mopeka sensors documented in the cerbo manual?
Also, is it a brand new cerbo or an older one?

It is a new mk 2 cerbo

Rules out the old Bluetooth issue.
So, it’s either range or setup steps missed.