@jemesouviens,
I see the certificate is fine for mail.ibroke.ca, tested here: https://ssl-tools.net/mailservers/mail.ibroke.ca
With iPhones you might need to re-create a mail account. Whenever I tested Let's Encrypt with mail_sni from DirectAdmin on MacOS 10.x certificates were accepted fine without an issue.
@sparek,
Creating a mail subdomain may be a solution, but it's not required.
I see the certificate is fine for mail.ibroke.ca, tested here: https://ssl-tools.net/mailservers/mail.ibroke.ca
With iPhones you might need to re-create a mail account. Whenever I tested Let's Encrypt with mail_sni from DirectAdmin on MacOS 10.x certificates were accepted fine without an issue.
@sparek,
Creating a mail subdomain may be a solution, but it's not required.