MS Bookings Email Reminders not working

[CH_500ABC]

As the title suggests the custom email reminders don't work not matter what I try (i.e. 15 mins, 30 mins 1 day etc). I have read various forums and tried creating new calendars, set up meetings in incognito mode, I have checked the message trace etc) but to no avail. Any help will be much appreciated because if I cannot get this to work we will have to try using a different service.

[#2]

@CH_500ABC 

Please submit a ticket to Microsoft support by completing the steps below.

• For Microsoft 365 Subscribers, navigate to Office.com home page.
• Select Admin | Support | From the dropdown menu, Choose New Service Request 
• Type in your problem which provides some suggestions (no way around this step)
• At the bottom of the screen, select Contact Support
• A Microsoft agent will contact you directly. (I have contacted them on several occasions.)

Teresa