If you've previously completed the manual email setup but are still having trouble getting your email account to operate, check and edit your iPhone SMTP port settings to ensure you're using the proper port numbers. Here's how to do it:

1. Go to the Settings tab.
2. Select Accounts & Passwords from the drop-down menu.
3. To set up an email account, tap on it.
4. Modify the SMTP server by tapping SMTP and the SMTP server you wish to change.
5. Utilize port 465 if you've chosen the option to use SSL. Otherwise, disable the Use SSL option. 80, 3535, and 25 are some more SMTP ports to test.