Run Energy Simulation 'Zone has no surfaces' error

Hello @M.Gkaintatzi and @AbrahamYezioro,
I also can’t run a HB simulation due to the same error. I’m trying to change the units so my HB model can run. But what exact tool should i use to change the units? I’m using LB_Legacy.
I’ve tried the helpful replies from @AbrahamYezioro and @chris here How to change units still same error.
But I can’t figure out exactly which tool/s to use and how to use them.
Thx so much!