Multicast Example

Could someone share a simple 3-router multicast config? I am having trouble getting it to work and I feel like I'm missing something obvious.

Here's what I have:

Sender - (SwitchA) -L3-p2p- (SwitchB) -L3-p2p- (SwitchC) - Receiver

All switches are configured with ip multicast-routing.
All switches are connected to each other with point-to-point L3 interfaces that participate in OSPF.
Interfaces between the three switches are set with ip pim sparse-dense-mode.
SwitchB has a loopback0 that is set with ip pim sparse-dense-mode.
SwitchB is the BSR and RP ip pim bsr-cadidate lo0 0 and ip pim rp-candidate lo0
SwitchA and SwitchC's output for show ip pim rp show the SwitchB lo0.
SwitchC lo0 interface has ip pim sparse-dense-mode.
SwitchC lo0 interface has ip igmp join-group 239.10.10.10
SwitchB can see 239.10.10.10 in the mroute table and can ping that address.
SwitchA does not see 239.10.10.10 in the mroute table and can not ping that address.
SwitchA shows show ip pim rp-hash 239.10.10.10 selecting RP of SwitchB lo0.

All switches can ping the lo0 of each other switch.

I'm at a loss and need a basic example to work off of. I don't understand why SwitchA will not send the ping to the RP to be forwarded to SwitchC.