Hola! That seemed to do the trick! Disabling:
// sendMacSet(MAC_RX2, “3 869525000”);
SendOTAA now joins TTN and payloads are coming through.
But alas, after 7 Successful transmissions:
Sending: mac tx uncnf 1 01
Response is not OK: no_free_ch
Send command failed
Probably to do with: