Why errors are vague
Discord keeps errors ambiguous on purpose, to protect people who block. That makes an accurate outside check impossible.
Mutual servers
By default, non-friends can DM you only if you share a server. Leaving a server alone is enough to break DMs.
Limitations on Discord
- Discord intentionally doesn't distinguish blocked from other DM errors.
- Server-level privacy is configurable per person.
- We have no access to Discord.