Is it permissible to form a new row behind the congregation when the front rows are incomplete due to praying between the pillars, and is the prayer of a person praying alone invalidated in this situation?

If the first row is not complete, a new row should not be formed until it is filled, according to the Prophet, peace and blessings be upon him, who said: "Complete the first row, then the one after it." It is disliked to pray between pillars, as the Prophet, peace and blessings be upon him, forbade it. However, if the row is interrupted by pillars, there is no harm in forming a new row, but one should not pray alone behind the row if there is a gap.