Why can't NagMon connect to my Nagios server?

The most common causes: the path field contains more than the base path (it should usually be just 'nagios' — no cgi-bin or status.cgi), the phone isn't on the same network or can't resolve a short internal hostname (try the IP address), iOS Local Network permission is disabled for NagMon, or the HTTPS toggle and port don't match the server. Test the server in a browser first: http(s)://yourhost/nagios/cgi-bin/statusjson.cgi?query=hostlist

Why do my credentials work in a browser but not in NagMon?

NagMon supports both Basic and Digest authentication automatically, so a working browser login should also work in the app. Re-enter the username and password carefully (watch autocorrect and trailing spaces), and verify against the same URL the app uses: the statusjson.cgi endpoint.

Why don't I see host groups, links, or host icons in NagMon?

Each has a server-side requirement: host groups need objectjson.cgi (Nagios Core 4.x JSON CGIs), links come from action_url/notes_url on the host or service definition and must be plain http/https URLs without unexpanded $MACROS$, and host icons must be defined in Nagios and present in the server's images/logos directory.

Why don't acknowledgements or downtime from NagMon reach my server?

Usually the Nagios user lacks command authorization in cgi.cfg (authorized_for_all_host_commands / authorized_for_all_service_commands, or contact-based rights). Check nagios.log for EXTERNAL COMMAND entries to see whether commands arrive. Also update the app: a command-submission issue affecting Digest-authenticated servers was fixed in NagMon 2.0.1.

NagMon Troubleshooting & FAQ

On this page

"Unable to connect" checklist
Authentication problems
"I don't see host groups / links / icons"
Commands not reaching the server
Data looks stale or incomplete
How to report a bug or request a feature

"Unable to connect" checklist

Check the path field. It should contain only the base path — usually nagios. If it contains cgi-bin, status.cgi, or a full URL, connections will fail. See the field-by-field guide.
Run the browser test. On any device that can reach the server, open:
```
http(s)://yourhost/nagios/cgi-bin/statusjson.cgi?query=hostlist
```
After logging in you should see JSON. If this fails in a browser, the problem is on the server or network side, not in NagMon. (A 404 here usually means Nagios Core older than 4.0.7 — the JSON CGIs don't exist yet.)
Same network? For an internal server, your phone must be on the same Wi‑Fi (or on VPN). Cellular data cannot reach 192.168.x.x.
Short hostnames. iOS often fails to resolve bare internal names like nagios when a desktop resolves them fine. Try the fully qualified name or the IP address.
iOS Local Network permission. For servers on your LAN, iOS requires explicit permission: Settings → Privacy & Security → Local Network → NagMon must be enabled.
HTTPS settings match the server. The Enable HTTPS toggle must match what the server actually speaks, and self-signed certificates need Allow Self-Signed Certificate turned on — see HTTPS options.
Non-standard ports. If the web UI lives on, say, 8443, set the Port field (or use host:8443 in the hostname).

Authentication problems

NagMon handles Basic and Digest authentication automatically, so anything that logs into the web UI should log into the app. When it doesn't:

Verify the credentials in a browser first, ideally against the statusjson.cgi URL above — that's exactly what the app requests.
Re-enter the password in the app. iOS autocorrect and invisible trailing spaces are classic culprits.

"I don't see host groups / links / icons"

These features depend on what your server provides, and hide themselves when the server can't deliver:

Feature	Server-side requirement
Host groups	`objectjson.cgi` available (Nagios Core 4.x JSON CGIs).
Links card	`action_url` / `notes_url` defined on the host or service; must be `http`/`https`, and URLs with unexpanded $MACROS$ are hidden.
Host icons	Icon images defined in Nagios and present in the server's `images/logos` directory.

Commands not reaching the server

Permissions: the user needs command authorization in cgi.cfg — see prerequisites. Read-only users can't submit commands from any client.
Check the log: accepted commands appear in nagios.log as EXTERNAL COMMAND entries. Present in the log but nothing happened? The issue is server-side processing. Absent entirely? Authorization or connectivity.
Update the app: a known issue where commands (particularly on Digest-authenticated servers) failed to submit was fixed in NagMon 2.0.1.

Data looks stale or incomplete

NagMon refreshes all tabs from a single shared fetch cycle; pull down to refresh on demand. If data seems frozen, check the Dashboard header — an unreachable server is flagged there per-server while other servers keep updating (how the Dashboard reports this). An incomplete picture with multiple servers usually means one of them is disabled or failing.

How to report a bug or request a feature

Feature ideas — and votes on other people's ideas — belong on the NagMon feature tracker. For bugs, email support from the app's Settings tab and include:

NagMon version and iOS version
Nagios Core version on the server
Connection style (LAN / VPN / internet, HTTP or HTTPS, Basic or Digest, standard or custom port)
The exact error text, and whether the browser test above works