Pairing issues w Ortho Remote and OD-4

Have two Ortho Remote (old, 2016 – 2017) both paired to my two OD-11’s. Trying to reboot one of them and pair to my OD-4 - but everything fails - have read the threads about “How-To” here - but nothing seems to work for me… firmware of OD-4 is 1.5.10