Shaikh al-Fawzaan hafidhuhallah was asked:
May Allah be good to you possessor of virtue, the questioner says: What is the ruling if a polytheist gives congratulations on the festival of the polytheists. Does a Muslim respond to it or not?
“No. It is not allowed to participate in the festival of the polytheists, not by giving congratulations in it nor responding to the one who congratulates in it. He says, ‘this is not allowed for me. We are Muslims and this is a festival of the disbelievers. We do not love it and we detest it.’ Yes. So it is not allowed to congratulate the disbelievers for their festivals and it is not allowed for a Muslim to respond to them if they congratulate because it is not the festivals of the Muslims. A Muslim is not happy by it. Yes. Likewise, the innovated festivals like the festival of mawlid and the other innovated festivals which the people of innovation do. Congratulations are not given on these either nor are they participated in. Yes. These are not festivals of Islaam. They are innovated festivals. Yes”
Faisal Ibn Abdul Qaadir Ibn Hassan