I have been trying for three weeks to sort this issue. At the moment my phone is my lifeline and I have two elderly relatives who need care. One in hospital and one not weight bearing at home. I cannot thank you enough - your post is so accurate and easy to follow. You have taken a huge weight off my shoulders.
My son has not been able to send email from his iPhone 6 for weeks. We tried deleting and re-entering the account which made no difference, and since his email settings were the same as mine I could not understand why his would not work. After reading your post the email problem on his phone was fixed in an instant. Thank you so much.
I solved this by downloading "My Mail" app from the Apple App Store. It set itself up automatically in seconds and worked fine. I then Googled for a solution and got Apple's mail app working (can't remember what the solution was though!) but to be honest I have now stuck with My Mail as I find it much better anyway
I'm aware of this but the problem is that it's very difficult to nail down the error that's causing your issue on the Iphone, which is why we need to do some diagnostics on a PC, to rule out other account issues.
I can receive but not send from my blueyonder account, Icloud emailing is OK.
Yes, I've now tried Thunderbird on my PC but couldn't send email.
This makes it look like there's an account based issue, but we need more info. Have a look at my post here: