Hi ​@Andrea23123 - Sorry that you’re running into this!

First thing we’ll want to check is the Troubleshooting Tool on your booking page - this will show you why specific times are not available. Just go to your booking page and select the troubleshoot button here:
 

Once you select this, select a date to see why those times are not appearing - Let me know if you need anymore help!

There is nothing else further down...

Hm very interesting - In this case, try editing the event, and going to the preview page. The troubleshooting button should show up there:
 

Can you let me know if you see it on this page? Thanks!

Dear David
Now I’ve found it with your advice. Thank you very much!
I have an entry in my calender, that it’s my kids’ schoolholiday. Nevertheless, I need these availability… how can I change it?

Even if I delete the schoolholidays in my calender, the availability dates don’t appear...

Glad to hear you’ve found it! Couple things we can look at next:

1. Make sure the calendar you’re using matches with what is in your Calendar Connections page: https://calendly.com/app/availability/calendar_settings
   (Whatever is connected, Calendly will check for conflicts, and any busy events)
2. You can try deleting the event, or marking it as free in the event settings here:

   

3. Check for any All-Day events that may be blocking off all of the availability for that day:

   

   If you do, delete it, or just mark it as free!
    

Once this is done, give Calendly 5-10 minutes to update. Let me know if you have any questions after checking these!