Outdoor Snowflake Lights Not Working?

Yesterday I strung 6 sets of hanging snowflake lights together outside. Those were plugged into one socket of an outlet. I had 3 other lit up decorations strung together and I plugged those into the other socket of the outlet. A few hours later all of the snowflake lights stopped working.

I reversed the lights in the outlet. Same thing happened; the decorations lit, but not the snowflakes. I switched extension cords, but that did not help. What do I do next? These took many hours and a tall ladder to hang. Take them all down is not what I want to hear.

By Debbie H.