In general, if you are not getting your desired network access there is either a misconfiguration or hardware/software limitation on the router. Please describe your network or provide a diagram.

If you indeed have a Model: TD-W8961ND then you have an ADSL modem without EWAN feature. Replace the Model: TD-W8961ND with any router that is not an ADSL modem combination.

Latest Firmware Build Solves this issue with configurable ms-dns options and VPN IP range within LAN DHCP range. Firmware Version: 1.1.0 Build 20141031 Rel.32628s Hardware Version: TL-ER604W v1.0

You wrote that you have a Model : TL-ER6120. I cannot replicate this problem with my Model : TL-ER6120 because it does not support Wireless. What Access Point or Router are you using for your...

All the configurations look correct. This is a mystery. I sent you a private message with instructions how to troubleshoot this.

IPSEC vpn has two parts. An IKE policy and a IPSEC/VPN policy. The IPSEC policy looks correct. What's in the IKE policy listed under Advanced IKE settings for both routers? Those should match one...