How to set up Teams calling policy disable PSTN on Defender for Cloud Apps

By Sai Kiran Pandrala · reviewed by Sai Kiran Pandrala, Editor Last verified: 2026-05-30

Why this matters

Set up teams calling policy disable pstn on a Defender for Cloud Apps device is one of the highest-volume how-to searches for the Microsoft 365 Admin category. Most users find the menu path inconsistent across Defender for Cloud Apps model revisions, so this guide gives a generalised path plus model-specific notes.

Pre-requisites

• A Defender for Cloud Apps device that's powered on and on the latest stable service version / OS.
• The Defender for Cloud Apps companion app or management tool installed and signed in.
• 5-15 minutes uninterrupted.

Step-by-step

1. Locate the setting. Open settings on your Defender for Cloud Apps device. For "set up Teams calling policy disable PSTN", the option lives under one of: General, Advanced, Connectivity, Accessibility, or a Defender for Cloud Apps-specific menu. Check the Defender for Cloud Apps user manual for your exact model if you can't find it.
2. Toggle the feature on. Confirm the on-screen prompt.
3. Configure sub-options. Most features have 2-3 sub-options (mode, schedule, paired device). Pick values that match your real-world usage pattern.
4. Save / apply. Some Defender for Cloud Apps models auto-save, others require an explicit Done / Save tap.
5. Test live. Trigger the feature in a real scenario to confirm the configuration is correct.

Tips that save time

• Pair this feature with a Defender for Cloud Apps automation / routine if the device supports it.
• If the feature relies on cloud sync, give it 1-2 minutes after enabling to propagate.
• For multi-user households / multi-admin teams, set per-user profiles so each user sees their preferred state.

Common gotchas

• Feature greyed out, usually service version too old. Update + retry.
• Feature works once then stops: battery saver / power saver mode is killing the Defender for Cloud Apps app process. Whitelist it.
• Feature works but with delay, usually cloud-sync latency; check internet speed and Defender for Cloud Apps service status.

Region / variant notes

Some Defender for Cloud Apps features are region-locked or only available on higher-tier SKUs. If your variant doesn't show "set up Teams calling policy disable PSTN" at all, check the Defender for Cloud Apps model spec sheet to confirm support.

Frequently asked questions

How long should the recovery / setup take?

For most Defender for Cloud Apps Microsoft 365 Admin cases, allow 15-45 minutes the first time. Repeats are usually under 10 minutes once you know the menu path.

Will this exact procedure work on every Defender for Cloud Apps model?

The procedure reflects current Defender for Cloud Apps behaviour. Menu paths shift between service version generations; verify against the manual for your specific model + revision.

Is the procedure safe in production / live use?

Apply during a maintenance window where possible. Capture pre-change state. Defender for Cloud Apps doesn't usually publish rollback procedures, so make sure you can restore manually.

Does this affect my Defender for Cloud Apps support coverage?

Standard operation per the user manual + applying official service version updates does NOT void support coverage. Opening managed services, third-party repair, or unauthorised modifications can void support coverage. check before going further.

Related guides

• All Microsoft 365 Admin guides → /microsoft/section/microsoft_365_admin.html
• All Microsoft guides → /microsoft/

Related fixes

Related guides worth a look while you sort this one out:

• How to set up Teams calling policy disable PSTN on Defender for Identity
• How to set up Teams calling policy disable PSTN on Defender for Office 365
• How to set up Teams calling policy disable PSTN on Defender XDR
• How to set up Teams calling policy disable PSTN on Microsoft 365 Apps (deploymen
• How to set up Teams calling policy disable PSTN on Exchange Online
• How to set up Teams calling policy disable PSTN on Microsoft 365 admin center

References

• Defender for Cloud Apps official support portal for your model.
• Defender for Cloud Apps community forum + Reddit threads.
• Vendor PSIRT / advisory page (where applicable).

Reference material, not professional advice. Validate with your vendor manual and follow local regulations.

What changed recently?

Fault diagnosis on this hardware goes faster when you map the symptom to a recent change:

• Did service version update in the last 7 days?
• Did the network (router, ISP, VPN) change?
• Was the device moved physically?
• Did paired devices (phone, hub, app) update?
• Were any accessories swapped in or out?

The answer narrows the root cause to a manageable subset.

Safety + preconditions

Before any work on this device:

• Unplug from mains for any internal-access procedure.
• flush cached state (circuit breakers in PSUs, residual battery charge) per manufacturer guidance.
• Use ESD-safe handling for boards and modules, no carpet, no wool sleeves.
• Avoid moisture; never apply liquids near vents or connectors.
• If you smell smoke, see scorch marks, or feel uneven heat, stop and escalate.

Quick verification

Before you walk away from this device fix, run through:

1. Reproduce the original trigger: does the issue reappear? 2. Check the device's status / health screen for any new alerts. 3. Confirm paired devices (app, hub, controller) reconnected. 4. Save / commit any configuration changes per the device's normal workflow. 5. Note the change in your maintenance log with date + service version version.

When to call How support instead

Escalate if:

• The same symptom returns within 24 hours of a clean fix.
• You see physical damage (burn marks, swollen battery, cracked PCB).
• The device is in support coverage and a hardware replacement is the cheaper outcome.
• Repair requires specialised tools you don't own (alignment jigs, calibration software).
• Following the official path keeps the support coverage intact, which matters more than the time spent.

More frequently asked questions

Will the procedure work on the international variant?

Some features and service version paths are region-locked. Check the model spec sheet to confirm your variant supports the menu option referenced. If you're outside the US/EU, look for the regional support portal.

How often should I run preventive checks?

Quarterly for most consumer devices; monthly for production / commercial devices. Set a calendar reminder so the device stays healthy between issues.

Will this void my support coverage?

Applying official service version updates and following the user manual will not affect support coverage. Opening managed services, jumping safety circuits, or using third-party parts can void support coverage in most jurisdictions.

Should I update service version first or last?

Update service version first if a release note specifically mentions your symptom. Otherwise, finish the troubleshooting flow first, then update; that way you can isolate whether the update or the underlying fix solved it.

Can I roll this back if something breaks?

Yes for software-level changes (service version rollback, config rollback). Hardware changes are usually one-way. Always back up settings before starting.

Field notes from real Microsoft 365 Admin incidents

When I work on set up Teams calling policy disable PSTN on Defender for Cloud Apps the rhythm I lean on is the one I have built over years of these tickets. Message Trace gives the truth that the user's Sent folder cannot, if a mail did not leave the org, it will say so in plain English. Service Health is the first tab I open before I touch a single setting; half the M365 tickets I work on resolve themselves once I confirm Microsoft has already flagged the incident. Microsoft Graph PowerShell is the tool I now reach for over the legacy MSOnline module, because the legacy module's deprecation timeline is finally serious.

Tools I actually reach for

For set up Teams calling policy disable PSTN on Defender for Cloud Apps on Defender for Cloud Apps the cheapest signal I can land usually comes from Microsoft 365 admin center, then Exchange Online PowerShell, Microsoft Graph PowerShell SDK, Office 365 SaRA tool when Microsoft 365 admin center cannot see the layer the fault sits in, and Message Trace for the cases where neither of those answers cleanly. That ordering is not academic. It matches the layers the failure tends to surface through, so the cheap signal lands first and the heavier tooling only comes out when the simpler answer does not hold up under scrutiny.

Verification I run before I close the ticket

Before I mark set up Teams calling policy disable PSTN on Defender for Cloud Apps resolved on a Defender for Cloud Apps unit, the verification loop below is what I actually run. Each step proves a different layer is green, and the order matters - the cheap checks gate the more expensive ones.

Connect-MgGraph -Scopes 'Directory.Read.All'; Get-MgUser -Top 5

If that one comes back clean, move to the next check. If it does not, stop and dig in there before layering more verification on top of a red signal.

Get-MgServicePrincipal -Filter "displayName eq 'Office 365 Management APIs'"

If that one comes back clean, move to the next check. If it does not, stop and dig in there before layering more verification on top of a red signal.

az ad signed-in-user show  # for cross-check against Entra

Only when every line above runs clean do I close the ticket and update the runbook with the timestamps.

Where I check first when the docs disagree

When two sources contradict each other on a Microsoft 365 Admin detail, the disambiguation order I lean on is stable. I usually start at status.office.com for the ground-truth view on Microsoft 365 Admin. I usually start at techcommunity.microsoft.com/category/microsoft365 for the ground-truth view on Microsoft 365 Admin. I usually start at admin.microsoft.com for the ground-truth view on Microsoft 365 Admin. Random blog posts and reseller wikis are signal, not ground truth, and I treat them as such until the references above either confirm or contradict the claim.

Pitfalls I have walked into on this exact path

The shortcuts that look smart on set up Teams calling policy disable PSTN on Defender for Cloud Apps have a habit of biting back. The pitfalls below are the ones I have personally walked into on a Defender for Cloud Apps unit, not things I read about. Microsoft Graph PowerShell is the tool I now reach for over the legacy MSOnline module, because the legacy module's deprecation timeline is finally serious. Message Trace gives the truth that the user's Sent folder cannot. if a mail did not leave the org, it will say so in plain English. When in doubt I revert to the slower path that the manual prescribes - the time I save by skipping it is always smaller than the time I spend cleaning up afterwards.

What I tell the next on-call

When I hand set up Teams calling policy disable PSTN on Defender for Cloud Apps off to the next person on rotation, the three lines I leave in the runbook are these. First, the symptom signature for Defender for Cloud Apps on the Microsoft 365 Admin family - not a paraphrase, the exact string that surfaces. Second, the diagnostic that gave the highest signal in the least time. Third, the exact verification command whose green output justified closing the ticket. That trio is what turns a one-off fix into a runbook entry the next engineer can use without paging me at three in the morning.

I also add a one-line note on the cost of getting this wrong. For set up Teams calling policy disable PSTN on Defender for Cloud Apps on a Defender for Cloud Apps unit, the cost is rarely the replacement part. It is the downtime, the second site visit, and the trust deficit you spend with whoever owns the asset when the fix does not hold. That framing keeps the next on-call from choosing the cheap-looking shortcut that ends up costing the most in elapsed hours and goodwill.