Cannot resolve issues Sending Windstream Email via iPhone mail app

I have searched (for months) and can’t keep the outgoing working without using the WiFi at home or logging in through Safari at Windstream website. I do have a desktop which is on maybe once or twice a month. The email settings include imap.windstream.net and smtp.windstream.net I read not to have SSL off, which I’ve done. My username and password ARE correct. I’ve deleted accounts and re-entered the information. It might work once or twice. I even turn my phone off and back on, still won’t work. It’s very frustrating because I can’t send emails away from home using the app.