Pinger question

[Troublemakeross]

Hello, needing to see if anyone might have a suggestion on how to fix this issue:

When hosting thru BHD and someone tries to join from pinger they receive the following message: bad key from server host.

It started happening after I opened the port. Before that pinger would show game as unknown and would freeze on joining session. Now with the port open, it shows the game in pinger but when person tries to join, it shows them joining server then immediately leaving server and they get the above bad key from server host message.

Anyone have any idea on how to fix this. Also please know, I am NOT computer savy , so make it as simple as possible with explanations, please and thank you.