Is it permissible for a marriage to take place over the phone, with the sheikh in one country and the couple in another, provided that the conditions for a marriage contract are met?

A sheikh is not a prerequisite for marriage. The offer of the guardian or his proxy and the acceptance of the husband are sufficient. The offer cannot be made over the phone; rather, the presence of the guardian or his proxy is necessary, although authorizing a proxy over the phone is permissible. If a woman does not have a guardian, she may appoint a suitable Muslim to act as one, but this appointment cannot be made over the phone.