I repeat: that port doesn’t matter
If you did read the guide, you would have seen this:
“The server also opens an “HTTP Server Port” by default on port 8888 TCP. This port is bound to localhost (127.0.0.1) and its purpose is currently unknown. It is not configurable. If AMP has assigned your instance a different port for the HTTP Server Port, it will show as red in AMP’s port status. This doesn’t matter.”