If I send a test email with postfix - gmail rejects it and gives me a link to their page explaining why I need to add a bunch of stuff so they know I'm not spam

If I send a test email with postfix - gmail rejects it and gives me a link to their page explaining why I need to add a bunch of stuff so they know I'm not spamming or fishing. Specifically I get this: gmail-smtp-in.l.google.com[173.194.207.27] said: 550-5.7.1 This message does not have authentication information or fails to pass 550-5.7.1 authentication checks. To best protect our users from spam, the 550-5.7.1 message has been blocked. Please visit 550-5.7.1 https://support.google.com/mail/answer/81126#authentication https://support.google.com/mail/answer/81126#authentication for more 550 5.7.1 information. d203si1756652qkb.228 - gsmtp (in reply to end of DATA command) there are tons of guides on troubleshooting mysql resource issues. Are they great? I don't know. Have I tried what is mentioned in many of them? Yes. I still have issues. I don't think it's just mysql though. I think it is a lot of little things that I'm slowly eliminating one by one.