Reason: connection to the client address 128.2.223.97:7869 is not allowed

If I telnet from the server back to the client on port 7869, that is successful.

What is possibly not allowing me to connect to the debug sessions?

Dale

Being able to connect via Telnet is confirming that you have a working connection with the server, but does not guarantee that communication on port 7869 will work. My guess is that a firewall (either on the remote server or on your side) is blocking connections on port 7869.

If you have SSH (not Telnet) access to the server, you may be able to bypass firewall restrictions by using the debugger over an SSH tunnel.

You need to check your debugger.hosts_allow, debugger.hosts_deny, and debugger.ports settings in php.ini and allow connection at that address and port.