Why hasn't my Gmail inbox been getting updated even though the Sync feature is on?

[AC Question]

my Gmail inbox has not been getting updated even though the Sync feature is on.

I've already checked that that it's synced properly on all fronts.

 

[B. Diddy]

Re: my Gmail inbox has not been getting updated even though the Sync feature is on.

Welcome to Android Central! Which device? It'd help to specify what all fronts means. First, is Auto-Sync turned on? Second, go to Settings>Accounts-Google>[your Google account]​--is Gmail checked on?