Setting up a Mastodon instance was not so hard. I mean, it took some tries to get it right finally, but generally I could understand what is happening and why there is currently a problem all the time during that process.
However, configuring that instance to send emails was a frustrating
experience for me, mainly due to fact that I could not find a reliable
source of error messages. In Mastodon, v3.4.1 at the time of writing, the
emails are pushed into sidekiq queues. It's interface is quite polished,
but the error messages did not show up for me, no matter how hard I clicked
around. Having no previous experience with sidekiq, I decided look
elsewhere.
Looking for a solution
Search results of about 30 pages shown different SMTP configurations, but
not a single one would enable sending emails from Mastodon instance to my
inbox. Looking into sidekiq, the problem of not sending emails was shown
there by precisely two scenarios, neither particularly helpful:
- The Processed jobs counter incremented, thinking that email was sent
- The job got oscillating between Busy and Retries, knowing there was a problem sending an email
Again, no emails were sent whatsoever. At the time I started becoming too desperate, I came up with this combination of configuration options:
SMTP_SERVER=smtp.example.com
SMTP_PORT=465
SMTP_LOGIN=[email protected]
SMTP_PASSWORD=very-strong-passphrase-here
SMTP_FROM_ADDRESS=[email protected]
SMTP_SSL=true
SMTP_ENABLE_STARTTLS_AUTO=false
SMTP_AUTH_METHOD=plain
SMTP_OPENSSL_VERIFY_MODE=none
SMTP_DELIVERY_METHOD=smtp
This particular configuration could be used with other mail servers that send emails using port 465 using SSL. Most of mail servers I am used to work specifically like this, so I am not entirely sure why I could not find this anywhere else, but maybe it is a localized problem.