Why can’t I open the weight watchers app

Hi judifromhedgesville. It sounds like something's corrupted.

Try deleting the app, then reinstalling it. Tap/hold the icon until the icons shake (wait for it...). Then tap the x to remove it. This will delete any data as well as the app. Open the App Store to reinstall it.

If you want to preserve any stored data, and you have iOS 11, go to Settings > iPad Storage and tap on the app in the list. Select Offload App to remove the app but keep the data. Then reinstall the app from the App Store. This option is not available with earlier iOS versions. Note that this may not work if the stored data is corrupted.

If this app uses an internet account, you might also check that your account is OK by logging in through a browser.

What happens when you try? Have you checked for an update?