Hi,
atm we don't have any SSL connection so I must use the old $paramMailerType='mail' method ;

When I try to send meeting invitation to ppl, it occurs that content-type is missing on mail header...
As a matter of fact, it's a plain text mail that is received and note a calendar type ...

I tried to investigate everything around my installation without success... Is there a bug with this method ?

I tried to send mail using demo web site... header looks like

....
X-Mailer: PHPMailer 6.0.6 ( https://github.com/PHPMailer/PHPMailer) 
MIME-Version: 1.0
Content-Type: text/calendar; charset="utf-8"; method="REQUEST"; charset=UTF-8

BEGIN:VCALENDAR
PRODID:-//Microsoft Corporation//Outlook 12.0 MIMEDIR//EN
VERSION:2.0
METHOD:REQUEST
BEGIN:VEVENT
....

With my installation

...
MIME-version: 1.0
X-Mailer: Microsoft Office Outlook 12.0

BEGIN:VCALENDAR
PRODID:-//Microsoft Corporation//Outlook 12.0 MIMEDIR//EN
VERSION:2.0
METHOD:REQUEST
BEGIN:VEVENT
...

Thx for help