Is that Owner Error? Operator Error? Usually I call it user error, but yes, it is most likely the cause. If your Moto remote is transmitting to your cable box, then it will transmit to your 8810.
Usually the problem is with the learn sequence conducted by the operator. In some cases it is because the learning memory is full, and even fewer cases simply a defective remote.

When learning, remember a few things:

The button you want to learn from the Moto remote should be pressed WHILE the red LED on the 8810 is blinking rapidly.

Try to keep the remotes about 1-2" apart, as the manual suggests. Try different angles, that sometimes works.

Try clearing all of the learning out of the key you want to learn to. You know that you can actually learn to more than just the L1-4 keys, right?

Try again and get back to us while waiting for your cable. You won't hurt anything, and when you get the cable, there is a ton of support for jp1.
Jim