Gmail users encounter a number of issues, including not receiving new emails. Reasons for this can include temporary server outages, insufficient account storage, or antivirus firewalls. Another reason that Gmail not receiving emails on iPhone is that IMAP may be disabled in the Gmail settings. This prevents you from receiving your emails from the server. Alternatively, you can delete your Gmail account from your iPhone and set it up again. Gmail's servers are typically where all of a person's email is stored. By deleting your Gmail account from your iPhone, you are not deleting anything from the server, so everything you have stored there will be available again when you set up the account again.
See also - Gmail Won’t Send Email Problems
