The ruling on praying in a direction other than the qiblah due to ignorance

Q: A question from A. M. A. from al-Khabar says: If a group of people prayed in a direction other than the qiblah because they did not know its exact direction, is it obligatory for them to repeat the prayer?

A: If they were in the desert and they exerted their effort (ijtihad) and prayed in the direction they thought was the qiblah after their effort, then they do not have to make up the prayer. However, if they were in a town, they must make up the prayer, because they are able to ask those around them about the direction of the qiblah.