Hi guys, Good news!!! New firmware to fix this problem is approaching!! just contacted the support team, got to know that tplink has already noticed this issue, and the fix work is undergoing.

IPsec will use port 4500 and port 500 when negotiate the tunnel, if there are NAT devices between these two routers, do the port forwarding configurations on the NAT device.

if your subnet mask is 255.255.255.0 then the max hosts for your subnet is limited in 255. it's in possible to set the DHCP range larger than that, may be you could have a try to shorter your subnet...

many reasons could lead to this problem, may be you should check your DNS server settings and have a try to for another website

tplink vpn router seems can't let the vpn ip address pools to be the same as local subnet. but still, i can set up the vpn connection up, check the router table, i find a new route to route the ip...

check if there are NAT devices at the WAN side of your router, if there are, then the change of the public ip address at the very front of your network(NAT deive), won't be noticed by your er604w....