I've been sending emails slowly using only SendGrid and MailGun (only a couple hundred per day) and out of nowhere, our emails are starting to hit the spam folder. We're sending some very simple cold emails (nothing that we thought was spammy) using plenty of spintax, no content that triggers mail-checker filters, and we've verified that we're not on any blacklists. I'm pretty sure we've got DMARC, SPF and DKIM all set up properly, but apparently that doesn't even matter? Is there someone in the group that's a deliverbility guru that can 1) get us out of GMail jail and 2) help us prevent this going forward? HELP!