How do I fix Calendar not sending email invites to specific addresses?

After I added my mailboxes from other providers calendar invites from my calendar were no longer being sent to those email addresses. These addresses were also added as recovery emails. I have done the setting of email notifications in iCalendar. Have removed the emails as recovery emails, have removed the boxes from calendar app. Still no email invites to only those two emails from my iCalendar. If I use the outlook app invites go out.