No dropdown on length of service.

Hi, I need to have variable length for appointments and I'm not been able to find the way for the dropdown to be displayed.

Look at the page

I setup a minimum time of 30 minutes and that's all that is being displayed. I need clients to being able to choose 30, 60, 90, 120... up to 300 min. I can give you access to the dashboard if required. Thank you!