When iOS is updates an iPhone or an iPad often the settings for your email are changed automatically by the software update, here is a quick guide to resolve this issue.
1) Start by unlocking your iPhone and clicking the settings icon
2) Then scroll down to the menu Accounts & Passwords and click this
3) In the next screen look for the account with your website address and then click this
4) Click the IMAP Account with your website address
5) Scoll down to the option SMTP with your website address and click this
6) Then click on the primary mail server that says on
7) Turn the Use SSL OFF so it is not green & change the server port to 26
Then click Done and the server will be tested and it will say verified!