A new MPLS VPN site can see nothing, but the other sites can see it

You work at the provider (AS 64500). Customer CUST-A has site 1 on PE1 (10.1.1.0/24) and site 2 on PE2 (10.2.2.0/24, PE2 not shown), both working for years. Yesterday site 3 (10.3.3.0/24, CE3 in AS 65003) was connected to the new PE3. The PE3 to CE3 eBGP session is up and PE3 receives 10.3.3.0/24. The customer reports site 3 cannot reach anything at sites 1 or 2. All PEs peer with route reflector RR1 for VPNv4.