I am pretty new to Orbeon forms. I created a simple form using xforms. I also tried to use xxforms which is the orbeon forms extension to xforms. But, whenever I used xxforms I got error. Then, I found out there is a problem with xxforms namespace.
The namespace which I used is xmlns:xxforms="http://orbeon.org/oxf/xml/xforms"
When I tried to open the orbeon.org, I got the 504 error.
Does the above namespace is proper? If not, suggest me the right one.
The namespace URI http://orbeon.org/oxf/xml/xforms is correct, although the custom now is to use xxf as prefix.
Maybe try with an existing example, like the Espresso Order.
There is also documentation on XML namespaces which you might find useful.