Summary
Multiplicities of an AssociationEnd must be consistent. MultiplicityMin cannot be '*' and MultiplicityMin must be inferior to MultiplicityMax.
Details
From a logical point of view, it makes sense that a minimum value cannot be higher than a maximum value. Furthermore, if the minimum value is '*' which means infinity, the maximum value cannot possibly be higher.
Tips
If you have a minimum multiplicity inferior to the maximum multiplicity or equal to '*', you must change one of these values in order for the minimum multiplicity to be inferior to the maximum multiplicity.