These are ust a few general points:
1. It doesn't matter if you never changed settings and suddenly have a failed registration state or are suddenly getting dead air. It doesn't matter if the service worked fine for years. Unless FPL servers are down, the problem is likely to be on your end.
http://status.fongo.com/
The problem may be related to a user not properly changing registration timers:
http://support.freephoneline.ca/hc/en-u ... redentials
Registration Interval: 3600 seconds (1 hour), Registration Expiry: 3600 seconds (1 hour), Failed Registration Re-Try Interval: 120 seconds
If your timers are wrong, you can end up with a temporary IP ban with the specific FPL SIP server you're attempting to register with.
The problem can also include a user not understanding that there may be a corrupted NAT connection that has developed in his or her router to the ATA that needs to be reset.
In some cases, changing local SIP port or X_UserAgentPort is the most effective way of, temporarily, fixing this.The problem can arise due to the router's UDP timeout being in excess of the ATA's Failure Retry timer.
2. If changing local SIP Port (in SPAxxx, PAP ATAs, etc.) or X_UserAgentPort in Obihai ATAs works, that means you are dealing with a corrupted NAT connection in your router. Typically, it's best to choose a random value between 30000 and 60000 to help thwart SIP scanners and circumvent faulty/buggy SIP ALG features in routers.
3. voip4.freephoneline.ca:6060 is used for dealing with SIP ALG issues. Rogers Hitron router and modem combos have SIP ALG enabled by default with no way for user to disable that feature without getting a Rogers tech to do it for you. Other modem/router combos that are issued by ISPs can also have SIP ALG stuck on. Typically, it's best to have your own router with SIP ALG/SPI disabled in it and stick the ISP's router/modem in bridge mode.
To better understand why SIP ALG is horrible visit
http://www.voip-info.org/wiki/view/Routers+SIP+ALG and read. Although SIP ALG is not broken in all routers (for example, the SIP Passthrough function in Asus routers doesn't seem to affect FPL), it is broken in a lot of them.
4. Proper device reboot order is always modem-->router (wait for it and your modem to be fully up, running, and passing data before turning on your ATA)-->ATA