Self hosted appwrite here, I previously sent emails using golang scripts over Gmails smtp servers.
I have this configuration im my .env File:
_APP_SMTP_HOST=smtp.gmail.com
_APP_SMTP_PORT=587
_APP_SMTP_SECURE=
_APP_SMTP_USERNAME=email@gmail.com
_APP_SMTP_PASSWORD="APP PASSWORD CONTAINING SPACES"
For some reason, sending the e-mails doesn't work.