Unable to connect MikroTik routers to CHR User Manager via RADIUS

I have a CHR running User Manager and multiple MikroTik routers connected to it over L2TP VPN.
Each router should authenticate Hotspot users through the CHR’s User Manager.

The problem is that the routers fail to communicate with the RADIUS server on the CHR.
On the routers, I set:
/radius add service=hotspot address=10.10.0.1 secret=12345

And enabled RADIUS in the Hotspot profile.

When users try to log in, I see this in the logs:
login failed: RADIUS server is not responding

On the CHR, /radius monitor shows the public IP working but the VPN IP (10.10.0.1) is not responding.
User Manager web interface works fine, but the CLI is not responding either.

I need help understanding why the CHR RADIUS is not reachable over VPN, even though routing and L2TP connections are active.

You need to configure the addresses of the client routers in user-manager as well.