Have you removed the cup and cleaned it well?
If you already did that, then do the following:
I have an AquaC Remora Pro. Same skimmer but larger. After a few months, the skimmer output gets reduced. Then, I know it's time to remove skimmer and clean it from top to bottom. Also, make sure pump is clean.
How I do it, is to remove it, clean it top to bottom and then, run skimmer with vinegar water, wait and see lot's of skim for a couple of hours or over night. Then, I rinse with water and place back in tank. Usually does the trick.
After cleaning, skimmer should perform better after a bit.