Hm... I add a dkim years ago, but maybe I created it incorrectly?
I need to figure out how to setup a dkim with my current server, if even possible. I may have to go for another service, which... would get expensive.
Ok, more correct research shows I do have a domain key, but for some reason, DigitalOcean only lets me label it 'gamersplane.com._domainkey.gamersplane.com'. I think it's supposed to be 'gamersplane.com._domainkey'?
Hopefully last follow up: I'm an idiot. I added the DKIM tags to the DNS and assumed that was all I had to do. Looks like I need to also attach it to the messages themselves, since the server uses it's own local SMTP, not my mail server (I'm currently unsure how to get the server to use my mail server). I guess more info = good?