When a user has given a consent, this will be valid until the CookieConsent cookie in the users browser expires. This means that the next time the same user comes to your website, the user will not be asked again for a consent.
When the consent expires, the first time the user comes to your website again, the cookie consent banner will automatically reappear and the user will be asked for a new consent.
If you are setting up Cookiebot on your own website, this is very likely the reason the banner doesn’t appear to you anymore. If you would like to see the banner, open a private browser window or incognito mode and enter your website’s URL – then the banner should be visible.