Firewall/NAT Settings

The firewall or NAT (Network Address Translation) settings could be causing the phones to lose their registrations.

Diagnosis: Check the firewall and NAT settings at the remote locations.

Resolution: If this is the problem, change the firewall settings to allow the SIP traffic through. You may see our SIP ALG guide to find your specific router.

Network Issues

Intermittent network issues could be causing the Snom phones to lose registration. This could be due to network congestion, packet loss, or an unstable internet connection at remote locations.

Diagnosis: You can run network diagnostic tests like Ping or Traceroute from the remote locations to the VOIP server to check for any network inconsistencies. Additionally, consider setting up network monitoring to get a better picture of what's happening over time.

Resolution: If the problem is network-related, you might need to improve the internet connection at remote locations, upgrade network equipment, or possibly even change ISPs. QoS (Quality of Service) settings on your routers could also be adjusted to prioritize VOIP traffic.

SIP Registration Timer

The SIP registration timer on the phones could be set too low, causing the phones to lose registration if they don't re-register in time.

Diagnosis: Check the SIP registration timer settings on the phones.

Resolution: If the timer is set too low, try increasing it. However, be careful not to set it too high, as this could cause other issues.

Phone Firmware

The firmware on the phones could be outdated or have a bug that's causing the registration issues.

Diagnosis: Check the firmware version on the phones and look for any known issues with that firmware version.

Resolution: If the firmware is outdated or buggy, you should update it to the latest version.

Remember that troubleshooting, it's often a process of elimination. You may have to go through several of these steps before finding the root cause of the issue.