When logging in to VS Connect, you may experience an error stating either "SIP 408" or "SIP 503" followed by "Service Unavailable". This could be caused by a few different reasons. The main cause is the network that you are on not allowing the connection to reach the VanillaSoft server. That being said, there are often some steps that you can take to work around this and resolve the issue.
Note: Since all troubleshooting is outside of VanillaSoft, this is not something that VanillaSoft supports. Any and all steps suggested are best efforts. For best troubleshooting, please involve your I.T. person, network administrator, or reach out to your internet service provider.
Step 1 -Wireless Internet
For all troubleshooting, wired internet is required as VanillaSoft does not support WiFi for VoIP lines. If you are connected to the internet via WiFi, it might be worth testing a wired connection. Depending on your network, the security settings in place might be more strict when connected via WiFi than there are while being connected via wired (Ethernet). If you're able to log in to VS Connect without issues while hardwired, try some of the bellow steps to see if you can get wireless to work.
Step 2 - Router Setting
Regardless if you are connected to the internet via WiFi or wired, if you have this issue, you may need to change some settings within your router to allow for this type of connection. One of the most common cause is the 'SIP ALG' setting. For best results, the SIP ALG setting should be disabled. For more information on this, please reach out to an IT person, network administrator, or your internet service provider.
Step 3 - Specified Port
If there is no change when you disable SIP ALG, you may need to open port 5060 for SIP traffic on your firewall. If you are unsure how to do this, it would be best to reach out to an IT person, network administrator, or your internet service provider.