Help with Comcast.net email using Outlook on iPhone

I have three Comcast.net accounts. My email works perfectly when using my  Xfinity web account and when using Outlook on my pc. However, when using Outlook on my iPhone and IPad, inbound emails are delayed (sometimes more than an hour) and outbound emails hang up in the outbox. On my Apple devices I have deleted and reinstalled Outlook as well as my Comcast email accounts multiple times. I have checked and rechecked my Outlook settings - ports, security settings, password. I have made the proper security settings on my Xfinity email page. Any idea what what I’m missing.