Cox-Yahoo email taking long time to reach/update on iPhone7

oldbobjr wrote:

Things worked great until the Cox to Yahoo migration..I am finally getting emails on my iPhone7 and Thunderbird. But my iPhone7 takes like 2-3 minutes to get the emails. The MAIL app only has FETCH available and the most it can look at is 15 minutes. I also put on the Yahoo Mail App and that gets the emails instantly with a badge and sound. Then I wait...and wait. if I open the MAIL app it does search for email but NO SOUNDS for new mail despite I have them scheduled to happen. Then it does find a new email. If I delete an email on Thunderbird 10 minutes later it is still in iPhone MAIL app..even if i open and close the MAIL APP

Can anyone provide some suggestions?

Yahoo account on Apple's mail app has always been notoriously bad, it is Yahoo way of pushing you to use their mail app instead of Apples.