Sudden sales drop on Facebook

Hello! I sell my products from my online store. Often happens that a product stops selling for 1-2 days. Optimization goes on the sales pixel, or on the pixel of the addition to the cart. The price of the lead is automatic. Before that sales can be stable a month or even more... I see clearly that facebook changed on its side, I do not change anything at all. And for 1 day the demand for the goods does not fall, this does not happen. Score of the ad is also perfect its 8-10 points. It remains only the facebook. Question: Tell me how to get the company back to sales . What should be done? For example, stop and restart the campaign after 1 day? Did not help ... Create a new company? or 5 companies? Thank you for spending time with my question!