Is it permissible to invite a specific imam of a mosque to lead the Isha prayer in another mosque for a special fee, without the permission of the officials, and does this entail sin upon those who extended the invitation?

It is not permissible for an appointed Imam to leave his mosque and pray in another mosque except with the permission of the authority that appointed him. Otherwise, he and those who assist him commit a sin. Furthermore, the issue of hiring for imamate is a matter of scholarly disagreement, with the majority of scholars holding that it is not permissible except out of necessity, fearing that people might not find someone to lead them in prayer. Among what has been reported regarding this is the dislike of praying behind someone who leads prayers for a wage, and the condemnation of an Imam who stipulates a wage for leading prayers in Ramadan.