ERROR when transferring calls through Quick Connections, in Amazon Connect.

I've been trying to figure out how my AWS Connect agents can transfer calls to each other via the quick connect feature in connect. Everything starts well but after a few seconds the agent interface hangs and goes blank leaving the agent without the ability to control his CCP and leaving the customer on hold until he decides to hang up himself.

We tried to see if it turned out to be a bug in the transfer flow we have, but found nothing out of the ordinary.

Other methods like Service Limit Increase have been tried but none with good results.

Any advice please?