iPhone won't access mail server
My iPhone has been flawless at getting my yahoo and iCloud email into my email (using mail app on phone). Recently (few weeks) it has delivered "error - see details" when updating email and says it cannot access yahoo or iCloud server. I can get email on my iMac mini with no problem, so isn't yahoo server. I must delete my yahoo account hen reinstall that same yahoo account and it will update and work for a few hours, then give me the same error. I must have deleted and reinstalled my yahoo account about 40 times. What is causing this and how do I change settings to make it stop, please? Thx for your help! JR
iPhone 7, iOS 12