2003 Hyundai Elantra instaling an engine

hello
I installed engine on the car, but as soon as I tightened the engine to the transmission, I heard loud clicking sounds. And neither the tourq converter nor the engine would turn. When I loosen the transmission from the engine, then the engine started turning and the tourq converter started turning. But when I tightened the engine with the tourq converter, the tourq converter would not turn again. Please let me know what I am doing wrong?

Thank you