We have an outdoor electrical outlet that is not working. When we plug in Christmas lights into both plugs, it trips the reset button. If we only use one plug on the outlet, it works fine, but the minute we plug something else into the other plug it trips the reset button and will not work until we unplug one of the outlets. Help... have to have all my Christmas lights up and working. Thanks!

Is this a GFCI receptacle? Does it matter which side you plug into first?

I've seen this kind of behavior before, but it was dependent on which outlet was used. The outlet wasn't GFCI, but the ground would break when one plug was used and the other was wiggled.

I'd suggest replacing the outlet.

The other scenereo is bad xmas lights, but you seemed to have elimininated that.