I'm running a mail server at home (on a small low-power server). Getting it right for incoming mails was easy (I have the chance that my ISP doesn't block anyth

I'm running a mail server at home (on a small low-power server). Getting it right for incoming mails was easy (I have the chance that my ISP doesn't block anything, so I can have port 25 open), for outgoing mails it's another story... but after setting up DKIM, SPF and DMARC (yes all of them were needed, especially for hotmail), deliverability is very good. As a backup, I created an address at Infomaniak, a Swiss hosting company, they give free e-mail (without ads -- their business model is rather selling other services like e-mail on custom domains, hosting, cloud services, etc.) with 20 GB storage (see https://www.infomaniak.com/en/free-email https://www.infomaniak.com/en/free-email). At the time I did it, they were requiring a Swiss mobile number (to limit the number of accounts people can get), not sure if now they accept numbers from other countries or not. In any case, it works great, both with webmail and standard SMTP/IMAP.