Is marriage to a Christian woman valid if the offer and acceptance took place, with the consent and knowledge of her guardian, in the presence of two Muslim witnesses via a phone call, and her dower was given to her as a valuable gift?

The marriage contract is not valid merely by the guardian's knowledge and consent. Rather, the guardian or his representative and witnesses must be present at the contracting session and hear the offer and acceptance. If the guardian, his representative, or the witnesses are not present, the contract is invalid, just as it is not permissible to عقد النكاح (conclude a marriage contract) through modern communication methods. If the spouses wish to continue their marriage, the contract must be renewed, fulfilling the conditions of validity. The guardian may appoint another person via telephone, provided that the appointed person meets the same conditions as the guardian. It is best for a Muslim to marry a righteous Muslim woman.