'Since all medical practitioners are competent and no competent people are underpaid, therefore no medical practitioners are underpaid.' Which fallacy is committed in the above argument?

The fault assigned is an undistributed middle term.

The middle term is 'competent', shared by both premises.

In 'All medical practitioners are competent' the middle is the undistributed predicate of an A proposition.

A categorical syllogism requires the middle term to be distributed in at least one premise.

A middle that fails to be distributed cannot firmly link the two other terms.

Where that connecting link is missing, the conclusion is not properly secured.