I’v got it work! Problem is strange but it seems that it related with communication chip on relay board. Relay started to work when I changed
Serial.begin(9600);
to
Serial.begin(115200);
I’v got it work! Problem is strange but it seems that it related with communication chip on relay board. Relay started to work when I changed
Serial.begin(9600);
to
Serial.begin(115200);