As above, be sure all wires are seated in terminal box all the way and be sure they are tight. Not that you are not capable but be sure power is OFF when you do this. It also might be a good idea to also remove the breakers and clean the contacts with alcohol and a swab, then let them dry and remount. What is odd is that only one side of your RV is affected. Is there anything on the other side that feeds off the breakers. If your Microwave pr fire place for example is on the left are those affected. They usually have their own breakers. Check the power at the post. If you have 50A see if you have the same voltage coming out of each leg.