I have gone through your Post and would like to help
Please ensure the Sprocket has the latest update
Make sure the printer is on and your mobile device is connected to the Internet.
On your iPhone device, open the HP Sprocket app.
Tap the Menu icon , and then tap your printer in the list.
The printer information screen displays.
Look for a printer firmware upgrade.
If a firmware upgrade displays, tap Get Firmware Upgrade, and then follow the on-screen prompts to complete the update.
If a firmware upgrade option does not display, the printer firmware is up to date.
If the issue persists please contact HP Support in your region for Service Options
1) Click on this link - www.hp.com/contacthp/
2) Select your product type below.
3) Enter the serial of your device.
4) Select the country from the drop-down.
5) Select the chat or get phone number options based on your preferences.
6) Fill the web-form and proceed further.
If the information I've provided was helpful, give us some reinforcement by clicking the "Solution Accepted" on this Post and it will also help other community members with similar issue.