Musnad Ahmad 27:1830

[Abdullah ibn Ahmad said]: I heard my father say: Yahya ibn Sa'id said: I did not find fault with anything from Ubaydullah ibn Umar, except for one hadith: the hadith of Nafi', from Ibn Umar, from the Prophet, peace and blessings of Allah be upon him: "A woman shall not travel a journey of three [days] except with a mahram." My father said: Abd al-Razzaq narrated it to us, from al-Umari, from Nafi', from Ibn Umar, and he did not attribute it to the Prophet (marfu').