1--Check that the starting battery is above 12.5 volts. The radio receiver can drain it if left on too long.
2--Check starting battery's terminals for clean/tight electrical connections.
3--Recheck remote's battery installation for correct polarity and clean contacts.
4--Confirm you have the correct procedure then repeat the remote/generator pairing operation again.
5--Try the manual key/pushbutton start. If that works, there's a problem in the remote.
2009 EF1000iS, 2011 EF2000iS, 1987 Honda EM-3500. (ready for anything!)