I've been trying for months to get email working on TankieTube. I finally got the local postfix server working but the problem now is that Spamhaus is blocking my domain and won't respond to my emails.

Edit:

Stop self-hosting your email and pay [provider]

I tried doing it with protonmail's API but emails originating from my application still get blocked, even though they should look to the relay servers like they're coming from smtp.protonmail.ch afaik. Emails sent from the protonmail web interface with the same return address deliver just fine.