I can reproduce this issue. The ATA is attempting to resolve myvoipms, in this example, which doesn't exist. That is, the Local DNS record is not being used. And then the ATA gets stuck in a loop trying to register with myvoipms (instead of what's listed in the local defined record) while internet access is absent.
Continuing to use the example provided by Gladdoo,
Under Service Providers-->ITSP Profile (voipms)--> SIP--> ProxyServer is set to myvoipms
Then, X_ProxyServerRedundancy is enabled.
When internet access has been established, the ATA still fails, in this example, to register with 67.205.74.179 until it's been made to reboot.
While this method of server failover may not be useful for
VoIP.ms in general, it does make me wonder if there's a potential fix for local DNS not working properly when the ATA boots before internet access has been established. Imagine there's a general outage in your area. ISP goes down. Power goes down. Power comes back up. Internet access is still out. ATA starts trying to register with Proxyserver instead of what's listed in the Local DNS record over and over and over again. Internet access returns. ATA is still not able to register. Registration still fails repeatedly by trying to register with myvoipms (0.0.0.0). User is forced to reboot ATA. Finally, the ATA registers with 67.205.74.179. In this example, ProxyServerRedundancy is useful when a server goes down, but, otherwise, there appears to be an issue when the ATA has booted up initially without internet access.