Check out mxtoolbox. Great website to check your mail server/ DNS etc.

Not what you asked for, but I started with self hosting my mail server ~ 1-2 years ago using mailu. Handles basically everything for me and I only needed to check my DNS entries + Reverse DNS.

Haven’t really had any problems since then. Only thing I had to make sure to set SPF to strictest setting (I believe drop), etc… that made the big ones MS and Google trust my mail instance without problems.

Only had a single mail rejected by Microsoft when I had my SPF set to junk instead of drop or something like that.