Anonymous Authority: the authority in question is not named 

Appeal to Authority: 
1.the person is an authority in the field 
2.experts in the field disagree 
3.the authority was joking

Is the authority identified?

Does he/she have the proper credentials?

Is the authority "up to date?"

Are you being influenced by the reputation rather than their evidence?

Has the authority been misquoted?

Is an authority in one field (e.g., basketball) being applied to another field (e.g., breakfasts)?