The category tree is small on purpose, but a few boundaries are not obvious. This is where each thing goes. If you get it wrong, a moderator moves the topic rather than closing it.
Running hMailServer
General support. The catch-all. If none of the categories below is clearly right, post here.
Installation, migration and upgrades. Installer failures, moving an install to new hardware, changing database backend, and anything that went wrong during an upgrade. Read §18 of the documentation first.
Linux. Packaging, systemd, file permissions, and anything specific to the .deb, .rpm or AppImage builds. Linux support arrived in 6.3.0. A protocol question that would be identical on Windows goes to General support.
Webmail, portal and Control Deck. The web interfaces themselves. Mail that never arrived is a delivery problem, not a webmail problem.
TLS certificates and deliverability. Certificate chains and renewal, TLS on the mail ports, SPF, DKIM, DMARC and reverse DNS. Anything ending in "the recipient rejected it" starts here. Documentation §8 and §9.
Anti-spam and message filtering. Scoring, blocklists, false positives, virus scanning. Documentation §10 and §11.
Guides and tutorials. Finished, tested write-ups. Not questions. If you are still asking, ask elsewhere and write the guide afterwards.
Automation and integration
Scripting and the COM API. Server-side scripts and anything driving hMailServer through COM.
REST API and integrations. The HTTP API, and third-party systems talking to it.
Rules, Sieve and routing. Server and account rules, Sieve scripts, routes and relays. Documentation §12 and §14.
Monitoring, metrics and logs. Reading the logs, JsonLogging=1 output going into Elasticsearch, Loki or Splunk, health checks and alerting. Documentation §16. A log line you cannot interpret that turns out to be a delivery fault still belongs in the relevant support category.
Development and roadmap
Bug reports. Reproducible defects only. Version including build stamp, platform, database backend, and the steps that reproduce it. Confirmed bugs are tracked at https://gitlab.com/hmailserver/hmailserver.
Pre-release builds. Anything that is not a signed release. Keep pre-release findings out of the support categories, because the answers there assume a released build.
Feature requests. One request per topic, so each can be discussed and closed on its own.
Community
Off-topic. Everything else.
Forum feedback and help. Problems with this forum: accounts, formatting, moderation, categories.
Managed hMailServer
For customers of the managed service. Do not post account or billing details in public.
Whichever category you pick, the checklist in the pinned posting guide still applies. Version with build stamp, platform, database backend, upgrade or fresh install, logs with credentials redacted.