How to debug email sending issues? (some recipients don't get some emails)

[sjjh (Simon)]

@merefield

I used a coding agent to summarise when emails are suppressed in mailing list mode:

Thanks, as an admin I mocked the user and I’ll go to each of it to debug the case:

• General: mailing list mode is activated in the user settings (via global setting)

@merefield

• The user muted the topic, category, or one of its tags.

• the topic is not muted (in topic view)
• no category is muted (in user settings)
• the topic does not use any tag (in topic view)

@merefield

• The user muted or ignored the author.

• no user is muted (in user settings)

@merefield

• The user cannot access the post - for example, it is in a restricted category.

• the user can access the post

@merefield

• The account is inactive, silenced, suspended, or awaiting required approval.

• the account is not inactive, silenced, suspended, or awaiting required approval

@merefield

• The user chose to exclude their own posts.

• the post is from a different user

@merefield

• The post or topic was deleted before delivery.

• the post (and topic) is not deleted

@merefield

• Previous delivery failures pushed the user’s bounce score over the configured threshold.

• the user received an email to another topic on the same day, thus the bounce score seems not have been active.

So what else can it be? How can I debug the issue further? I’m a little lost… :-/