In IPv6 router gets the Router solicitation message, but not respond with Router advertisement

We setup a IPv6 network with two ubuntu systems and we make one PC as HOST and other as ROUTER(based on the concept of SLAAC). The host sent the "Router solicitation" message, but the router not respond with any "Router advertisement".

The corresponding configuration we done for router is

sudo sysctl -w net.ipv6.conf.enp1s0.autoconf=1
sudo sysctl -w net.ipv6.conf.enp1s0.accept_ra=2
sudo sysctl -w net.ipv6.conf.enp1s0.forwarding=1

Can you please suggest any solution?

From the comments we understand that we can't make it as a router without the help of a deamon. We use the radvd deamon to solve this.