I recent bought a TP-Link ER605 VPN router to replace my old Linksys LRT224 Dual WAN Gigabit VPN Router. The old Linksys was used to connect to two different offices, the remote end being a Sonicwall SOHO in both cases. 

I created the exact same VPN configuration on the ER605, and it doesn't connect to either office. I am not a VPN newbie, I have used Cisco ASA, Juniper, Sonicwall for creating site-to-site VPNs since 15 years.

Sonicwall has a static IP, the ER605 doesn't. So I am using NAME as the local ID type. On the Sonicwall side I have toggled between email address, firewall identifier and Key Identifier. I don't know what is the identifier ER605 is sending to Sonicwall.

But the Sonicwall keeps repeating the same error on its side.