Monitoring Benefit
The ActiveSync HTTP OPTIONS Command test verifies that the server responds to the OPTIONS command and advertises the protocol versions a client needs. It is the first exchange in any ActiveSync session, so a failure here means mobile devices cannot even begin to connect.
This is the same test as Exchange Online - ActiveSync HTTP OPTIONS Command Status, run from a remote probe rather than from the ENow web server.
Why the probe version matters
The value of running it from a probe is location. The ENow web server usually sits in a data centre with a clean path to Exchange; your users do not. A probe placed at a branch office tests the path those users actually take, including that site's internet egress, proxy, firewall and DNS.
That makes the comparison between contexts the real diagnostic:
| Pattern | What it points at |
|---|---|
| Fails from every probe and from the ENow server | Exchange, the namespace, or the test account. Not a site problem. |
| Fails from one probe only | That location. Egress, proxy, TLS inspection or local DNS. |
| Fails from every probe but not the server | Something common to the probe path — a shared proxy or a firewall rule that does not apply to the data centre. |
| Fails from the server only | The web server's own configuration, not the service. |
How do we verify the monitoring test results?
- Run the Microsoft Remote Connectivity Analyzer from a machine at the same site as the probe — not from the ENow server, or you lose the point of the test. Use testconnectivity.microsoft.com and choose the Exchange ActiveSync test.
- Test with a second mailbox known to work, to separate an account problem from a path problem.
- Check whether the probe itself is reporting. If the probe has stopped checking in, its indicators turn red and the detail page says the agent has not reported in for a given period — which means the test result is not current and the probe, not ActiveSync, is the problem. See Remote Probe - Connectivity Status.
Where the settings are
Probe test accounts and endpoints are configured in the ENow Admin Console under Server > Tuning Policy > Settings > Probe Configuration > Configure Probes…. Thresholds for probe tests are held separately from the server-side ones, under Server > Monitoring Policy > Thresholds, in the Remote Probes section. Changing a server-side threshold does not change the probe's.
Where this is shown in the console
This check appears under Exchange Remote Probes > ActiveSync, which you can open directly:
https://<ENow web server>:20080/MailscapeWeb/Exchange/ExchangeActiveSyncRemoteProbe.aspx?server=<PROBE>The probe name in the query string carries a suffix — for example LONDON-EXCHANGE rather than LONDON. You can also reach the page by selecting the probe's row under Exchange Remote Probes on the dashboard at /MailscapeWeb/Default.aspx.
Common warning or error results, and potential solutions
| Result | Potential solution |
|---|---|
| HTTP 401 from the OPTIONS command | Authentication. Check the test account's credentials and whether Conditional Access is blocking the probe's location — see Conditional Access and ENow: Why Device-Based Policies Block Monitoring and, for the addresses to trust, Network Requirements: Ports, Endpoints and Proxy Configuration. |
| Certificate or TLS errors from one site only | A TLS inspection appliance at that site is presenting its own certificate. Exempt the Exchange namespace from inspection, or trust the appliance's certificate on the probe. |
| Timeouts rather than errors | The request is not arriving. Check that site's egress rules and proxy configuration for the Exchange namespace on 443. |
| Intermittent failures at one location | Often a load balancer with one unhealthy node behind the namespace, or a saturated link at peak. Compare against the times of day the failures cluster. |
| The result never changes | Check the probe's detail page. If it reports that the agent has not checked in, the probe is the issue rather than this test. |
Reference: The ActiveSync OPTIONS command returned an HTTP 401 Error | Microsoft Learn
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