You firewall is not allowing calls to your SIP phone. If you can do so now then your problem was with your routers firewall configuration. Reboot your router and VoIP device and check if you can make/receive calls. Disable SIP Application Layer Gateway (SIP ALG) if applicable.Ĥ.) Try disabling your firewall (turn it off completely) briefly. Disable Stateful Packet Inspection (SPI) if applicable. From your router’s web configuration page (usually under configuration / firewall / advanced settings)

For detailed instructions consult your router's user guide or the manufacturer's web site.ģ.) Some routers alter SIP packets with the default configurations which creates VoIP service problems. Most VoIP firewall isues are resolved by router firmware upgrade. Please make changes one at a time and reboot your router and VoIP device each time to see if the problem is solved.ġ.) Please check that you have Internet connectivity (try to view a few web sites) and check if your router/firewall settings have changed.Ģ.) IMPORTANT Upgrade the firmware (firmware is similar to software) on the router. Try the following solutions to resolve the issues. These issues are often due to your router's firewall (also known as NAT) blocking certain operations of the VoIP telephone adapter.

You experience quality issues such as choppy conversation or one person can't hear the other.

Your calls have a maximum duration of exactly 10 minutes.

You hear a busy signal in the middle of the call.

Incoming calls go directly to voicemail without ringing your VoIP VoIP phone.

You cannot make outbound calls or when making outbound calls you hear a busy signal even though the person you are calling hears a ring.

VoIP light goes out intermittently or constantly.

If your VoIP telephone adapter is placed behind a router or a combined modem/router, you may experience problems with your VoIPVoIP service.

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