It is narrated from Uthman (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "A person in the state of ihram should neither marry nor arrange a marriage."
Hadith Referenceمسند الإمام الشافعي / كتاب الحج / 866
Hadith Takhrijاخرجه مسلم النکاح باب تحريم نكاح المحرم ، وكراهة خطبة (1409)۔