Cannot connect xbee pro s3b to xctu

I have tried everything I have read to no avail. I need to configure two xbee pro modems to use with a pixhawk. They won’t connect to the XCTU. Any help???

Jaffrican, what is the full part number for the XBee modules you are working with? The part number will be on the white label on the module and should be something like: XBP9B-DMS-001.