Why is there a drop in traffic after using Cookiebot?

Using Cookiebot on your website will have an effect on how and when traffic is measured in your Analytics - and other factors also contribute to explain changes in the recorded traffic. This is explained below.

If you see a sudden change in your analytics data after switching from manual to Automatic Cookie Blocking mode, this is an indication that Cookiebot is working as intended and that your cookies are being blocked more efficiently now than they were previously under your manual implementation of prior consent.

No data recorded for users who do not either opt in or opt out

Any recorded drop in traffic is primarily related to the fact that no data is registered for those users that simply ignore the cookie consent banner and leave the website again without having either opt-ed in or opt-ed out. This is further described in this article: The Cookiebot banner and your Google Analytics data

The used consent method (also) has an impact on whether data is recorded or not

The type of cookie consent banner you are using on your website can have a further impact on the analytics data:

• If you are using a banner with the consent method 'explicit consent', the banner will stay on the website until the user submits a consent. This means, that if the user ignores the banner, it will not go away, no opt-in or opt-out will be made and no data will be recorded. This is what explains part of the "missing traffic" that some users report.
• If you are using a banner of the type 'active consent', the continued use of the website will constitute a consent. If you have enabled 'on scroll' for example, the user scrolling on the first visited page will constitute an opt-in and data will be recorded (if that opt-in includes statistics cookies).

This means that if the consent method is set to 'explicit consent' the number of users ignoring the banner - and not being measured in analytics - is likely higher than for the 'active consent'.

Using Google cookies/trackers with multiple purposes 

If you are using Google cookies that have marketing purposes (such as the 'collect' tracker), then you can set it up to send a signal to Google that the statistics parts/cookies should still be allowed even if the user opts out of marketing cookies. Please note that since the marketing category cannot be pre-checked according to GDPR, many users will not actively tick the marketing category to allow marketing cookies (relevant if you are using a banner of the type 'multilevel' or 'inline multilevel' with tickboxes. Please see New: Implement Google Analytics using Gtag (Global Site Tag) for how to send the correct signal to Google to allow statistics cookies without a consent to marketing cookies.

Data not recorded for returning visitors who opt-ed out

Do keep in mind that if a user opts out of statistics cookies, any return visits from that user will not be measured. 

If you are seeing unusual spikes in your traffic on the dates that the Cookiebot scanner crawls your website, please see: I see (unusual) spikes in the traffic on my website - is it caused by your scanner?