Reference: Fataawa al-Hajj wal-‘Umrah waz-Ziyaarah – Page 101
Question: What of the one performing Hajj being unable to find a place [to rest] in Muzdalifah during the night of ‘Eed. What is the ruling?
Response: Whoever is unable to find a place [to rest] in Muzdalifah, then that which is clear is that there is nothing required of him because all obligatory acts are ‘forgiven’ if one is unable to perform them [subject to Islaamically acceptable conditions].