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Most call problems come from a network or device issue you can correct yourself. Work through the steps for your symptom below — if the issue persists afterward, contact support with the affected extension numbers so we can dig in quickly.

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Dropped calls or one-way audio

Dropped calls and one-way audio (you can hear them but they can’t hear you, or vice versa) are usually caused by a local network or device issue.
1

Power cycle the phone

Unplug the phone from power for 15 seconds, then plug it back in and let it fully restart.
2

Fix the two most common router settings

On your router, enable Multicast and disable SIP ALG. These two settings cause most VoIP call-quality problems.
3

Rule out the handset

If only one side can hear audio, reseat the headset cable or switch to speakerphone to confirm it isn’t a headset problem.
4

Rule out the device

If the problem is limited to a single extension, swap that phone with a known-good one to confirm whether the device is at fault.
5

Reboot the base station for cordless phones

If the affected phones are cordless (DECT), reboot the base station they connect to — not just the handset. Unplug the base’s power (and network cable, if separate) for 15 seconds, then plug it back into the same port.
If you’re working from home or over Wi-Fi, place a test call over a cellular hotspot instead of your usual network. If the call works on the hotspot but not on your Wi-Fi, your router is interfering with the call — ask your internet provider to disable SIP ALG (on some provider-managed routers this is done by switching the router to bridge mode). On a managed corporate or healthcare network, the most common cause of one-way audio is a firewall blocking VOXO’s return audio traffic. Ask your IT team to whitelist VOXO’s media subnet 140.235.248.0/24 — see Firewall IP Whitelist for the full list of ranges and ports to allow. Contact support if issues persist after a restart and router-setting check, or if multiple extensions are affected at the same time.

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A desk phone won’t register

If a phone shows “Account Unregistered”, displays “No Service”, or says the phone is disabled, it has lost its connection to the system — usually a network issue.
1

Power cycle the phone

Unplug the phone’s power cable (and network cable, if separate) for 15 seconds, then plug it back in.
2

Check the network connection

Confirm the network cable is fully seated at both ends and that your switch or router has power.
3

Factory reset a desk phone

If the phone still won’t register, factory reset it by holding the OK button (center of the directional pad) for 5–7 seconds and confirming.
The hold-OK reset above is for desk phones. A cordless (DECT) handset such as the Yealink W73H ignores that gesture — reset it from the handset menu instead: press OK, open Settings, go to System Settings (or Advanced Settings), choose Handset Reset, and enter the PIN when prompted (the default is 0000). You can see whether the extension is online in Extensions. Contact support if the phone still won’t connect after a factory reset, or if it connects but immediately goes offline again.

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An extension shows stuck on a call

If a phone screen says you’re stuck in a call, or an extension shows busy in the Operator Panel when no call is actually in progress, the extension’s call status has gotten out of sync with the system.
1

Power cycle the phone

Unplug the phone from power for 15 seconds, then plug it back in and wait for it to fully restart.
2

Check for a parked call

If a call is sitting in a park slot, pick it up to clear it. Connect users can see parked calls in Your department → Parked Calls.
3

Confirm the status in the Operator Panel

Open the Operator Panel to check whether the extension still shows on an active call after the restart. The Active Calls list is read-only — there’s no end-call control to clear a stuck entry yourself.
Contact support if the extension still shows on a call after a power cycle and no parked call is waiting — only support can clear a stuck extension status from the backend. Include the affected extension numbers so we can clear them quickly.