Hello LadyT777,
If the Mail app on your iPad is slow to load and is closing unexpectedly, follow these steps to start:
• Close and reopen the app
Force the app to close. Then open the app to see if it works as expected.
• Restart your device
Restart your iPhone or restart your iPad. Then open the app to see if it works as expected.
This information and more can be found here: If an app on your iPhone or iPad stops responding, closes unexpectedly, or won’t open
If this continues, does this happen with every Wi-Fi network you connect your iPad with or only when it’s connected to a specific network? Let’s also follow the guidance in the ‘If you need help sending or receiving mail on your iPhone, iPad, or iPod touch’ section of this article: If iCloud Mail isn't working
If something else is happening, please provide more details and if you are getting an error of some kind.
Cheers!