UCM Pro help

I bought UCM (https://codecanyon.net/item/freelance-project-invoice-crm/2621629)
and I cannot get past the login loop(i login, refreshes login page). He doesn’t offer support anymore and I have no idea where to fix this. If anyone knows a solution or willing to work on it I would appreciate it.

That developer is well known with disaster support and low quality . rate him 1 star and ask for refund. He is respond every 6 month on comments.