iOS 10.x and 11.x (iPhone, iPad) Email Account Settings for IMAP

Here are our instructions for setting up your email account on your Apple iPhone. These instructions apply to iOS 10.3.x and 11.2.x. 
  1. Go to Settings.
  2. Select Select Accounts & Passwords (if using iOS 11.x) or Mail (if using iOS 10.x).
  3. If using iOS 11.x skip to next step. If using iOS 10.x then Select Accounts.
  4. Select Add Account.
  5. Select Other.
  6. Select Add Mail Account.
  7. Enter your Name in the Name field. (ex: John Smith)
  8. Enter your E-mail Address in the Email field. (ex: john@company.com)
  9. Enter your Password in the Password field.
  10. Enter any kind of description you want in the Description field. (most people will simply enter their e-mail address or use something like "Work" or "Personal" or "Company Name").
  11. Press the Next button.
  12. Press the IMAP tab.
  13. Your Name, Email and Description should already be filled out.
  14. Enter mail.atlantisnet.com as the Incoming Mail Server Host Name.
  15. Enter your E-mail address as the Incoming Mail Server User Name. (ex: john@company.com)
  16. The Incoming Mail Server Password field should already be filled out.
  17. Enter mail.atlantisnet.com as the Outgoing Mail Server Host Name.
  18. Enter your E-mail address as the Outgoing Mail Server User Name. (ex: john@company.com)
  19. Enter your Password in the Outgoing Mail Server Password field.
  20. Press the Next button.
  21. iOS will now verify your setting which will take approximately 1 minute.
  22. At the very least, you must enable Mail for synchronization.
  23. Press the Save button.
  24. Select the account you just added from the account list.
  25. Click on the account again.
  26. Click on the Outgoing Mail Server SMTP server for mail.atlantisnet.com.
  27. Click on the Primary Server for mail.atlantisnet.com.
  28. Verify the Server is Enabled.
  29. The Host Name, User Name and Password fields should already be entered.
  30. Enable the Use SSL option.
  31. Verify Authentication is set to MD5 Challenge-Response.
  32. Verify Server Port is set to 587.
  33. Click the Done button.
  34. Click the back link which should show as < Account.
  35. Click the Advanced link.
  36. Enable the Use SSL option under Incoming Settings.
  37. Verify Authentication is set to MD5 Challenge-Response under Incoming Settings.
  38. Verify Server Port is set to 993 under Incoming Settings.
  39. Click the back link which should show as < Account.
  40. Click the Done button.