Staff Members not receiving a confirmation email when customers book appointments

Up until about a month ago Bookings was working great at my company. We primarily use Bookings for clients to book consultations with staff on-site. Customers are able to book appointments through an I-Frame that is available on a scheduling portal on our company website. This functionality used to work great, however we've been losing functionality little-by-little since our first issues started popping up.

First, our staff stopped being able to edit the notes on their appointments through Outlook, which was fine we could work around that however inconvenient it is.

Next, a few staff members failed to receive confirmation emails or appointments through Outlook leading to them not even knowing that they're supposed to have a consultation at the time set by customers.

Now, there are a lot more staff members experiencing the issues mentioned above. Seems like every staff member is having issues receiving the meetings in their Outlook inboxes and on their Outlook calendars. This is very stressful for our staff members because they continue to miss meetings, which does not reflect very well on the company.

Basically I want to know why this issue seems to have suddenly cropped up. Is it possible that the i-frame implementation we use is no longer valid with newer versions of Bookings? Or is the implementation Bookings has with Outlook becoming deprecated in favor of the Bookings web portal?