OS: CentOS Linux 7.5.1804 (Core)
Panel: Plesk Onyx Version 17.5.3
So all is good for people using iPhones to send/receive email on my server EXCEPT when the LETsENCRYPT cert renews.
client domain has SSL via plesk using LETsENCRYPT.
my plesk server host has LETsENCRYPT (this is host.domain.com that is actually sending email)
all email clients have a notification that ask, do you want to trust this cert EXCEPT the iPhone.
is there are way around it?
my solution is to not use LETsENCRYPT and buy a 2 year ssl for my server host domain.
The current solution of deleting settings and email account on iphone (and adding them back) is NOT a good one.