K8057 433MHz 2ch receiver

Dear,
The receiver recognizes the signal of a garagedoor opener “Normstahl”
I manage to set relay n° 2 in the desired mode (either ON/OFF or time delayed 30 sec)
BUT : after the set up ; the receiver does not respond to the transmitter signal.

What do I do wrong ?
Thanks for your reply,
Bert Lathouwers

Please note that this receiver will only work with the dedicated transmitter from Velleman (either K8059 or VM108)