We're sending email through SendGrid. We first create these emails with SMTP in our Apache server with PHP. When we send this email with the .ics file attached we need to import the event into the customers' calendar automatically.
Right now we managed to add it only in Gmail accounts. In all other like Hotmail, MSexchage etc. we had no luck! The email goes, but in order to add the event to the calendar, you have to click on it and click on the CTA add to calendar. Is this a server issue? Is something we forget?
Kostas,
What happens with an ics attachment depends very much on each users setup and what they have said should happen with ics files. Mine open in a text editor for testing for example, not in my google calendar. Also it depends what email address it is sent to. Even google invitations don't work if we use one email address, even though it is linked to the google email.
I very much doubt that events would be added totally automatically just by receipt of an email with ics file attached. Imagine the spam abuse that might happen if that were the case.