Make sure they are using http://rcwpcanada.x10.mx/ , NOT https://rcwpcanada.x10.mx/
They can also get the raw error using telnet. Below is an example. Bold, underlined text is input:
telnet rcwpcanada.x10.mx 80
Trying 198.91.81.4...
Connected to rcwpcanada.x10.mx.
Escape character is '^]'.
GET...