Problem with RSVP

Hello. I have a problem with the email that the system send to invitees.
On my cellphone works ok but on my outlook only i have a plain text of the emal server like this:

Delivery-date: Sat, 10 Mar 2018 11:16:38 -0300
Received: from na23.servidoraweb.net ([167.250.4.23]:55859 helo=mailserver01.servidoraweb.net)
by toran.servidoraweb.net with esmtp (Exim 4.87)
(envelope-from <info_web@faevyt.org.ar>
id 1eufIc-0047wA-HM
for gustavo.martinez@netconar.com.ar; Sat, 10 Mar 2018 11:16:38 -0300
Received: from localhost (unknown [127.0.0.1])
by mailserver01.servidoraweb.net (Postfix) with ESMTP id 910E42A0508
for <gustavo.martinez@netconar.com.ar>; Sat, 10 Mar 2018 14:03:20 +0000 (UTC)..........


And on my hotmail account the ics is not soported.

Please some help
Thanks