No heartbeat Packets Received pop up

Hi, I’m facing an issue where no heartbeat is received every time I want to connect with my (Bluetooth) TX in Mission Planar. I tried with every baud rate and checked the parameters of serial 0 and serial 1 as Mavlink2 is set correctly. I connected my trans receiver to a Telem 1 port, so I checked every relevant parameter regarding this. But could not solve the issue. Also, I changed the TX (T12) with another by binding with the receiver (skydriod). Help me out!