When I tried to have someone connect to the server. They received an error message 1. Any idea why?

What is the error? Did you read the thread just below? https://atvo.appgineering.com/Forum/Thread/133

I attached the error message.

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I do believe I forwarded the port. I tried it without the theme loaded but still keep having this issue.

Does it work on your local computer? Just open ATVO twice, run a server on one instance and client on the other. Then use "http://localhost:1337" as the URL (assuming you put 1337 as the port).