hi. thanks for the reply. actually, i used the heliohost server's own mail client setup, for iphone there's a profile configuration that's downloaded onto the phone. There it automatically sets the incoming mail server host name: javalan.helioho.st, user name: spider@javalan.helioho.st, over SSL port 993. this worked before on my iphone, but recently just gives me an error trying to reach server. i checked the SSL certificate in my plesk control panel (javalan.helioho.st account), and i do have the Let's Encrypt certificate selected. I don't quite know how to update it.
Carlos