Why do Zoom calender invites need to be manually downloaded into calender?

[SamPerry1982]

Hello

A number of my customers don't turn up for zoom meetings.

They all point out the same issue

When Zoom sends an invite, they click accept but this meeting does not automatically appear in their calendar.

They need to manually download the invite from the Zoom email.

Why does it not automatically add to their calendar, like all the other providers do?