Based on your response, the CQ8700/8900 does support the @PrintByXerox weblet.
I will have the reseller partner verify firmware and upgrade if necessary as well as reviewing the Proxy server settings.
The first thing you should do is verify that the proxy server is set up correctly via the device IP web page under Connectivity > Setup.
If that does not work, check for the most current version of firmware and update the firmware. After this is complete, attempt to push the @PrintByXerox applet from the AppStudio again.
Please let me know if you need any additional assistance.
Xerox Mobile Print Admin
Does the CQ8700/8900 support the @PrintByXerox Mobile Cloud Application?
I have a reseller partner who was attempting to download @PrintByXerox applet from AppStudio to a CQ8700, and he received an error message.
I wonder if the device might require a firmware update.