Apple Mail download performance is sporadic

My Apple mail is configured with my Yahoo mail ID, but Apple mail download performance is sporadic. My new mail is always present if I use Yahoo webmail (a terrible interface), but Apple mail is another story.

With the Apple mail app, sometimes it downloads new mail, other times it doesn’t. Sometimes it downloads the header, but not the body. Sometimes it won’t even download the header; the progress icon just spins around forever. I’ll try again later and everything downloads fine. Then 30 minutes later I’ll see a new number next to a folder name — an indication that a new email is on the server — but Apple mail won’t download it. Or it will download the header, but not the body.

I experience this frustration every day, all day long. It seems to have gotten worse after iOS 16 was introduced. My wife, who has the identical phone and mail setup, experiences the same thing.

We have 500 Mbps internet service. Mail performance is always perfect with Yahoo webmail, but as I mentioned earlier, I don’t like the interface and much prefer Apple’s, especially because I have a lot of subfolders off my Inbox and am constantly going in and out of them.

I use many mail rules to autosort my Yahoo mail, which means that I usually have to go into each subfolder before the Apple mail program will download that subfolder’s mail.

If I were to take a guess, I would say that Apple is throttling my mail usage when I use the Apple mail app. It let’s me download mail, then it doesn’t — even when I know that new mail is on the server.

I have verified that all of my mail config settings are correct in Apple mail, and Yahoo webmail works perfectly, so it appears the problem is happening on Apple’s mail server, which sits between Yahoo’s mail server and my device.

Can anyone recommend a solution for fixing the sporadic download behavior of Apple mail?

iOS 16.2 on iPhone 8 and iPad