I have experienced it at some point in 2017. That day I learned about helpful websites you can use to rate your email (which is helpful because you can realize

I have experienced it at some point in 2017. That day I learned about helpful websites you can use to rate your email (which is helpful because you can realize that your domain/IP is blacklisted somewhere for previous owner was spamming from it). In 2017 I learned I have to add DKIM and SPF and had no problem with spam since then. But this thought me a lesson to go through ratings every now and again, just to stay up to date with new mechanisms that are being used by biggest email providers (gmail, yahoo, etc).