Reminder emails for booked sessions not always being sent

I have a problem with reminder emails not sending consistently from the Wix Booking app. Other emails turned on in the booking settings seem to work ok.

Wix Booking system email reminders. Inconsistent levels of emails being sent; between 10%, 40%, and yesterday it got up to 80%, which got me hopeful it is working as it should, but today is at 0% so far.

Booking confirmation emails and other emails go to clients, but I am going to monitor them more closely.

I have worked through some DNS changes to make sure both Wix and Outlook emails are supported for routing emails. GoDaddy manages the DNS, and MX records and SPF records are correct.

I have seen a note that sometimes Outlook may quaranteen emails, and I wonder what I can do to get Wix and Outlook to work better together for my client.

There are no more DNS changes to make and my client and I never had these issues on her site on Squarespace when we had similar functionality.

Can anyone suggest anything else I can try?