**Each training session must have at least 10 kids, maximum of 12 kids per session. If lessons are less we will contact you and possibly postpone until the session until the following week.
Captcha HttpHandler appears not to be registered.
If you can see the Captcha image, it's safe to disable this troubleshooting check (documentation).
Please make sure your web.config file includes the following declarations:
<add verb="GET" path="BotDetectCaptcha.ashx" type="BotDetect.Web.CaptchaHandler, BotDetect"/>
<add name="BotDetectCaptchaHandler" preCondition="integratedMode" verb="GET" path="BotDetectCaptcha.ashx" type="BotDetect.Web.CaptchaHandler, BotDetect"/>
If the Captcha HttpHandler is registered, it could also be inaccessible due to your Url Routing/Rewriting settings.
SessionTroubleshooting: CustomSessionIdManager not configured (documentation).