When did you change your hosting? Did the drop immediately after that change? Have you checked recent Google algorithm updates. Depending on the timing, it could have been the Google update instead. If it's related to hosting, you may want to talk to your hosting provider to see if they are blocking a large amount of traffic, resulting in origin errors. There's also the possibility that you lost organic search traffic based on the hosting server location but that is not something we can know for sure because it's tied to Google's algorithm and non-public information.
As for your other question, you can go to Ezoic Ads -> Ad Positions to view a table of ad placeholders and edit sizes. You can also use the Ezoic Chrome extension to view and edit ad placeholders visually.
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