A service provider runs an MPLS L3VPN for a customer that uses RIPv2 as the PE-CE routing protocol on both sites. On PE1, the VRF 'CUST-A' learns customer routes from the CE via RIPv2 and redistributes them into MP-BGP. At the remote PE2, these routes are received via VPNv4 and must be redistributed back into RIPv2 toward the remote CE. After configuration, PE2 advertises the routes to its CE but the remote CE marks them as unreachable. Which action on PE2 resolves the problem?