Normally sites have to wait a few days, but it can be a wait of one day or a couple of weeks. Whilst the system is fully automated, the set-up requires humans input!
So - once you have changed your nameservers to point to Ezoic, our technical team will review your site, set it up and check for any conflicts with the system. Although it is rare to find these, when we do we fix them not only for your site but also to ensure the next site with a similar conflict is handled automatically - so we fix it for all sites.
Sites are reviewed in order that their name servers are changed. Some sites take longer than others tor review and test - during this period you continue to collect revenue in your account and track activity in the same way you always have done. From the perspective of your visitors, nothing has changed, so the length of time it takes to review the site is not really that important (you're losing nothing); it's more important to allow the technical team to complete a thorough review and test of your site before going live.