"Connection to lobby failed" Assetto Corsa Server Please Help!

I tried to port forward on my Hitron router. After, after hitting "Start Server" and waiting, it says
"RESPONSE: ERROR,INVALID SERVER,CHECK YOUR PORT FORWARDING SETTINGS
CONNECTION TO LOBBY FAILED, ATTEMPT NUMBER 1". I did everything in the video.

Please help!

Video I used.


Also, sorry if this is a repost...