XBee S1 Pro and S2C communication

Currently, FC is using Kakute F4 and telemetry is using XBee S1 Pro and XBee S2C.
I would like to use Mission planner software to make wireless connections with telemetry.
Both telemetry protocols are 802.15.4.
However,
Mavlink connecting > No Heartbeat.(No Heartbeat Packets Reveived)
and I get an error message “No Heartbeat Packets Reveived.
Please let me know the solution.