“VATICAN CITY, June 23 (Reuters) - The Vatican on Tuesday reaffirmed a long-standing rule that only an ordained priest or deacon can give a sermon at a Catholic mass, rejecting a request from German bishops to broaden the practice and allow sermons by women or other laypeople.”
διάκονος, the word used to describe Phoebe can also mean messenger, courier or servant
Romans 16:2 so that you may receive her in the Lord with the worthiness of the saints, and so that you may be of assistance to her in whatever task she will have need of you. For she herself has also assisted many, and myself also.
she was being received, so I think that she was a messenger/courier and servant of the Church