Does not fasting the expiation for an oath or the existence of a vow prevent the supplication from being answered, and does the Hadith: "The fasting person has a supplication that is not rejected" apply to one who fasts for the expiation of an oath?

Whoever owes an expiation for an oath or a vow and has not fulfilled it despite having the ability and capacity to do so, is persisting in disobedience. This may prevent the acceptance of their supplication, because involvement in disobedience necessitates the non-acceptance [of prayers]. This is indicated by the Almighty's saying: "Indeed, Allah only accepts from the righteous." It is permissible for a fasting person to supplicate for whatever they wish, concerning matters of this world and the Hereafter. The supplication of a fasting person is answered from the beginning of the day until its end, due to the general statement of the Prophet, peace and blessings be upon him: "Three whose supplications are not rejected: the fasting person until he breaks his fast, a just ruler, and the oppressed."