Does Discourse retry bounced emails? Can the number of attempts and time interval be configured? [Taking into consideration bounce penalty score points, I understand.]
I don’t think discourse itself retries to send emails. However, the ESP (e.g. mailgun) may retry sending emails unless a hard-fail is reported by recipient email server. Such bounces can be reported to discourse through their API.
This is generally the job of the mail server, not Discourse per se.
As @itsbhanusharma correctly noted, if you have bounce handling configured, Discourse will eventually stop mailing people whose emails consistently bounce. These individual bounce scores decay over time so Discourse will “try again” over time.
I have the Discourse bounce handling enabled, but I have to tread very carefully because with Amazon SES if you get too many bounces you can go above a health/reputation threshold and get suspended.
I will confess that the retry policy and algorithm used by Amazon SES is completely opaque to me. I am not even sure if they do it. Hence my enquiries about Discourse capability in relation to retries.