I moved servers, and consequently all domains to my new host about 2-3 days ago. Everything has gone smooth except for an issue regarding emailing a mailbox hosted on Google Apps on my own domain from the server, for example.
18.104.22.168 hosts example.com. I have a PHP script on the server hosting example.com to mail firstname.lastname@example.org for certain things. It will never arrive in my email@example.com inbox hosted by Google Apps since I've moved servers. It worked fine before.
I know mail is being sent because I can edit the script to email for example: firstname.lastname@example.org or email@example.com instead of firstname.lastname@example.org and both arrive in my inbox, though in spam (probably unrelated). I thought this was because the server IP wasn't the same as my old one, and the system was using my old server IP so emails couldn't be forged, so it would need 24-48 hours to propagate the new IP and the mail would start being received. However it's now been almost 72 hours and I still can't email anything on the @example.com domain.