A new gateway in network is causing domain controller fail

Hello,

Seeking for a ransomware protected backup and low cost want to use a second router (as gateway) to backup in "external" FTP server

Using Windows static route command route add, a small router TPLINK and a PC with Filezilla FTP server

We create a funtional "external" FTP server, it works fine in tests.

But every time we attach this router TPLINK our domain controller in LAN can't give DHCP and shared folders are unreachable ???

I check DHCP is disable in TPLINK router

route add 192.168.0.0 mask 255.255.255.0 10.1.8.1

Thanks