Gmail - cannot get mail error

Hi guys,

Here is a weird one.

I have just moved to iPhone 7 from iPhone 5s. While setting up the 7, I restored from 5S iCloud backup.

I use gmail for email and contacts and have re-entered password and 2-step auth code for Google accounts.

Every time I open Mail all the new emails appear on the list BUT then I get an error pop-up "Cannot Get Mail. The connection to server failed". I have to tap OK to close it.

So I can send and receive all emails but every time I open Mail I always have to OK that error message. Also, the 'Last Updated' date at the bottom of the screen does not change to Just now.

I tried removing and adding the Google accounts in settings and the problem persists