https://www.mail-tester.com/ https://www.mail-tester.com/ is a useful tool for testing. Gmail is hit or miss, even when dkim/spf/dmarc are setup correctly. It

https://www.mail-tester.com/ https://www.mail-tester.com/ is a useful tool for testing. Gmail is hit or miss, even when dkim/spf/dmarc are setup correctly. It may work 70% of the time, but it becomes a constant guessing game if you inboxed or went to spam. If you're using DO/Vultr/Linode, there may be issues with noisy neighbor IPs, but it still sucks that you may get penalized for no fault of your own. It seems like there is no incentive for Gmail to play friendly with small mail servers.