The Gmail app for the iPad has an intermittent issue where you will get the error message, "Something went wrong. Please try again later." This problem does not happen on every iPad and previous workarounds no longer seem to work. The problem became more apparent with iOS 10 and has continued with iOS 11. Some users have reported success with logging in through the Chrome app and then downloading/installing the Gmail app.
If you are not experiencing this issue, then continue using the app as normal.
If you ARE experiencing this issue, you can try the suggested Chrome workaround. If this does not work, we recommend using either the Mail app on your iPad or logging in to gmail through your browser.