Do you have power at the outlet where the unit is plugged in? If not restore power to that point. Next, check the main breaker to determine if it has tripped. It may look like it is on but to verify, turn it off and then back on. It should click into place. If that does not work and your trailer has a genset with a transfer switch. Check the transfer switch to make sure that it has not failed. It may be locked into the genset side and not switching back to shore power. If you are running the genset and do not have power make sure the breakers on the front of the genset are on.