Hi,
If you are a new seller or selling in a Category with restrictions, you may have weekly or monthly limits on the number of items you can list or revise.
In general, the limits get a periodic review (usually 90 days), but it may very by item, category, your sales record, etc. It most often happens on categories with high counterfeit rates/problems.
Hate to ask, but what are you selling?
Danno