Help with Outlook/Gmail

I need my email outlook configuration set up properly. All of a sudden not all but some of my emails go to peoples junk folder. It never happened before just started. One in particular is the same domain address that I send it to and it goes into junk. People who I send often too, goes into junk even when I hit reply to that specific email. My email is a google account (gmail). I've only recently changed hosting provider for the website not the email as it's with google.