Please double check that you have entered the correct code. Try the automatic programming feature on your remote to cycle through all the codes until you find one that works.
Weak batteries may cause the remote to only operate one device or to operate intermittently. Replace weak batteries with new alkaline batteries.
Finally, make sure that nothing is blocking the signal from the remote control to the TV or digital receiver. Make sure you are pointing the remote control at the correct device and that the correct corresponding device button on the remote has been selected.