Hello Bonzadog,
Welcome to the HP Support forums. I understand that you are having problems setting the ePrint feature of your Officejet 6500 E710n printer. Thank you for including how the printer is connected, I appreciate it.
The error message you received was it while you were trying to add your printer to the HP ePrint mobile app? If so had you connected your mobile device to your wireless network instead of being on a mobile data plan network?
Let's ensure that the ePrint feature of the printer has been setup. Were you able to enable the web services for the printer? Once the web services is enabled you should be able to add the printer's ePrint email address to the HP ePrint app. If you are having issues enabling the web services and are prompted with a proxy error message, please set a manual ip address and manual DNS servers. I've included a link to another post on the forums with screen shots on how to set the manual ip address and manual DNS servers. The post also includes the information to enter for the manual DNS servers.
Once the web services is enabled you will get an instruction sheet with a claim code on it. If you have received this instruction sheet please use the document "Getting the Printer Claim Code". If you have the instruction sheet and it is less than 24 hours old (the claim codes expire after 24 hours) then please use the document "Setting Up A Custom Email Address for ePrint" to personalize your printer's ePrint email address.
You indicated that you would like to print from your Apple iPhone and your Samsung tablet. I have included the HP ePrint Mobile App FAQ document and the HP All-in-One Printer Remote Mobile App FAQ. The AiO app is helpful if you want to scan directly to your mobile devices.
