My outgoing email gets misidentified as spam

  • YNH version 11.0.11
  • Bought VPS
  • Have access via webadmin & ssh

Forgive me if this has been answered elsewhere but I have been unable to find an existing post about my problem:
My outgoing email seems to be getting flagged as spam by recipients and so they don’t get to see it.
Could this be a problem with the domain?
Is the nohost.me domain blacklisted by the likes of gmail and outlook? If I buy a dedicated domain for my email could that solve the problem?
Or does my nohost.me subdomain need some kind of third-party certification?
I am new to self hosting and running a server in general and any advice would be much appreciated.
Thank you

Maybe you can find answers to your questions here :