W3 Cache with affiliate links..

Hello everyon! I'm using W3 Cache (also using wordfence plugin) and Easy Azon for amazon affiliate product links. A few weeks ago I made some updates to the WP version and some plugins and than my conversion rate dropped systematically till I got 0 sales per day (which is never happened before). But when I deleted all my cache with the W3, the conversion rate popped up to the usual for some days and than agian get lower and lower and than agian I delete the cache and it is popping back. Someone can tell me please what's wrong with the affiliate links and the cache, why is it happening?

I don't have knowledge about cache, actually I barely know what it is, so what can cause this issue?

Caching is basically just storing a static version of your page. So it shouldn't cause any problems, however, the only thing I can think of is if you're aff links are dynamic (i.e they change from time to time - or if the Easy Azon plugin "recloaks" them it might conflict with caching.) Try using a more standard caching plugin if you really need to cache or just drop caching