What is the ruling on congregational prayer in a mosque that deviates from the Qibla by 17 degrees? And is it necessary to adjust the rows with a string despite the slight deviation, or does "what is between the East and the West is a Qibla" permit prayer without disfiguring the rows? And is it permissible to abandon this mosque and move to other mosques?

Facing the Qibla is a condition for the validity of prayer. Those near the Kaaba face its very essence, while those far away face its general direction. The majority of scholars believe that a slight deviation from the Qibla does not invalidate the prayer. Your past prayers may have been valid, but it is necessary to adjust the rows in the future to correct the direction. There is no harm in using a string or similar tool to adjust the direction of the rows towards the Qibla; in fact, it is preferable. It is best to pray in the neighborhood mosque, and those in charge of it should meticulously adjust the rows, as some imams consider prayer invalid due to such a deviation.