Main number returning "not in service" to all external callers for 3 days — internal Zoom calls work fine

Hi ​@Tai Braga 

i checked my suggestions against ai.zoom.us

“how to troubleshoot the following zoom phone problem:When anyone calls our main number (assigned to our Auto Receptionist) from an outside phone (cell or landline) they hear "the number you dialed is not in service." However, calls made from within the Zoom environment to the same number work perfectly.What we've checked:- The number is assigned to our Main Auto Receptionist and shows "Normal" status- IVR menu is properly configured and working- Business hours are set to 24/7- No changes were made to our settings before the issue started- Tested from multiple external phones (cell and landline), all fail with the same message- Other direct user numbers on our account also cannot receive external calls

04:41 AM

Thought process

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Here’s a structured troubleshooting guide for your Zoom Phone issue where external callers hear “the number you dialed is not in service,” but internal calls work fine.

🧩 Step 1: Verify Number Assignment and Status

• Confirm that the main number is still assigned to the correct Auto Receptionist or main site.

  • Go to Phone System Management → Phone Numbers.
  • Check that the number’s Status is “Assigned” and Type is “Toll” or “Toll-free.”
  • If it shows “Unassigned” or “Pending,” reassign it to the Auto Receptionist.

• If the number shows “Normal” but external calls fail, it may indicate a carrier routing issue rather than a Zoom configuration problem.

🔍 Step 2: Check Call Routing and Business Hours

• In Auto Receptionist → Call Handling, ensure that:

  • The Business Hours are set correctly (you mentioned 24/7, so confirm no hidden holiday or closed hours).
  • The IVR menu or forwarding destination is valid and active (e.g., not pointing to a deleted user or call queue).

• Test by temporarily routing the Auto Receptionist directly to a known working user extension.

  • If external calls still fail, the issue is likely outside Zoom (carrier or number porting).

⚙️ Step 3: Test Other Numbers

• Since you mentioned that other direct user numbers also cannot receive external calls, this suggests a system-wide inbound routing or carrier issue.
  • Check if outbound calls from Zoom work.
  • If outbound works but inbound fails, the inbound carrier path may be broken.

🧾 Step 4: Check Number Porting or Carrier Status

• If your numbers were ported to Zoom, verify that the port completed successfully.

  • Go to Phone System Management → Ported Numbers.
  • If the port shows “Completed,” but inbound calls fail, contact Zoom Phone Support to check carrier routing tables.

• If the numbers are Zoom-provided, open a Zoom Support ticket and include:

  • The affected phone numbers
  • Call examples (time, caller number, and result)
  • Confirmation that internal calls work but external calls fail

Zoom can trace the inbound call path to identify whether the issue lies with the PSTN carrier or Zoom’s routing.

🧰 Step 5: Optional Diagnostic Tests

• Use Zoom Phone Logs:
  • Go to Phone System Management → Logs → Call Logs.
  • Check if inbound calls from external numbers appear.
  • If they do not appear at all, the calls are not reaching Zoom (carrier issue).
  • If they appear but fail internally, it’s a Zoom routing or configuration issue.

✅ Summary of Likely Causes

Recommended Next Step

Since multiple numbers are affected and all show “Normal” but fail externally, the most probable cause is a carrier routing or trunk issue.
Open a Zoom Phone Support case and include:

• Affected numbers
• Example call timestamps
• Confirmation that internal calls succeed

This will allow Zoom to trace the inbound call path and coordinate with the carrier if needed.”

my opinion is that zoom aic 3.0 provided a well reasoned response.

thanks,  eliot