We are sending a lot emails on a daily basis with calendar events attached to them as ICS files. This always worked and the calendar events attached to the emails would automatically get added to the Outlook calendar as invite.
Lately this feature stopped working while we did not change anything about the way we send those emails. Outlook now doesn't add the invites to the calendar anymore but shows the emails like any other email with the ICS appointment as attachment.
I already tried everything I found on the web, have gone through every setting in Outlook and on Outlook.com, but that didn't seem to do the trick. Also it seems like it has something to do with an update or something, since every single one of our customer has this problem.
Can anyone point me in the right direction?