actually there is nothing named ''blocklist'' but ''blacklist'' is there.and no one can blacklist any expatriate while exiting doha unless there is a order from court.

so if there is no case filed against you there is nothing to worry about your business visit visa.

please do not make your self confuse. if you are having NOC from previous sponsor for visit visa how is it possible that you are in blacklist?

hope you all the best.