Hi ​@Leonie08270! 

Thanks for reaching out to us - In this case, the first thing we’ll want to use is our built-in Troubleshooting Tool. This allows you to look into specific unavailability reasons to see why dates aren’t showing up correctly. You’ll want to go to your booking page, then select the Troubleshoot button here:

Then select the day thats having this issue. You can follow this article here for more details: How to use Calendly's Troubleshoot Tool

Let me know if you have any questions!

Alright, I did the trouble Shoot. The Problem is exactly what I was expecting: is an overlap. so two hosts have an event at the same Time. The second event at the same time is not available in the calendar tool. So no client can book the second event with the other host.

So what do I do ?

The next thing we’ll want to look into are the specific availability settings for each host. When you go to edit your event, select the Availability dropdown, then there should be an additional dropdown for each host included in the event.

Could you go through and make sure each host has that same time available? If they do, can you send a screenshot my way? I can take another look from there.