Hi, if the VPN terminates on an IOS router, then the split tunneling does not "block" anything. It simply decides which traffic is sent through the tunnel and which traffic is sent in clear text (as in Internet traffic).
If the router has ACLs on the outside interface, that could be blocking the traffic (even VPN traffic).
Make sure the desired traffic is part of the split tunneling rule and that if there's an ACL, it allows the traffic to pass.