I have just changed from POP to IMAP on Go Daddy. My desktop works fine so far. I can send and receive. HOWEVER, my iphone 6 will only receive. I have deleted and reinstalled and it "verified" but if I try to send an email it says the address is rejected by the server. CHAT help said it must be a provider problem but I don't see how that can be.
I've had this problem since I got a new phone a few months ago (I switched from iPhone 6 -7). I've spent hours on the phone with tech support and when they were unable to fix it they send me to my carrier (T-mobile) who said it was the mail server. Now I have to send all my email from my iCloud account (which, of course, points to the problem being Go-Daddy.) Really annoying.