Erroneous node numeration, mbndg > numnu

I am trying to simulate a single element tests in CB with a BBM model. The problem is that when I try to do only one element I get this error:

Erroneous node numeration, mbndg > numnu

Which means: Global matrix bandwidth > number of unknowns.
Can anyone tell me how to simulate a single element in code bright please? My method is obviously not working.

You cannot simulate a single element; you need al least more than one due to the algorithm used by Code_Bright to reduce the matrix bandwith.

Dear Code_Bright Team,

thank you for the response!

Best regards,
Boris