A customer asked whether a long power outage means pairing the transmitter and receiver all over again.
No. Once paired, RX480E-4 and RX480E-4C keep their pairing after a power outage.
You do not need to repeat the Learning button sequence just because the receiver has been without power. When power returns, try the remote you already paired.
Resetting the receiver is different. A reset clears all paired transmitters, so those remotes will need pairing again. It is worth keeping that distinction in mind before resetting a setup that worked before the outage.
If the remote does not respond, first check that the receiver has power. That symptom alone does not establish that the pairing was lost.
See the RX480E-4 manual or RX480E-4C manual.