I created a 1st, 2nd, 3-6th level character.

I started with Rogue, Cleric, and ended up with a 3rd with four levels of Bard.

I have the attributes needed for Cleric and Bard, however the character sheet didn't enforce the need to have Dexterity to multiclass from the first level.

 If multiclass requirements unchecked on the character preferances page of the character builder?

Some people want to create characters that do not meet the ability requirements so DnD beyond allows this to be an option via this switch.