Why is Email taking about four minutes to open on some, and not all devices? Many people have posed this question on forums, and I have not seen a response from Apple. It does not occur in on my IPad mini, or my phone; however it happens on my large screen IPad which is the device I prefer to use for reading email and opening all apps, except for Audible which i typically use on my iPad mini, and my Iphone.
Many Apple users Email taking entirely too long to open.
You will not get a response from here your question is better served here as it is developer related: https://discussions.apple.com/welcome