If your mail app keeps refusing to sync your emails, it is probably because Gmail considers it to be a “less secure app”. Instead of syncing your mail, you get warning messages asking you to login by a web browser. You may already have tried to do that, but your mail app still won’t sync with Gmail. Let us tell you what’s going on, and how to resolve this problem once and for all. Link : How To Unblock Gmail Restrictions On Outlook & Less Secure Apps2
