The Wireless light blinking blue means the printer is in wireless setup mode and ready for a new network connection.
You can connect it using the HP Smart app. Download HP Smart from 123.hp.com or your device's app store, open the app, tap the plus icon, and follow the steps to add the printer to your Wi-Fi.
If your router has a WPS button, you can press and hold the printer's Wireless button for 3 seconds until it blinks, then press the router's WPS button within two minutes.
If that didn't work, the mode may have been activated accidentally. Try restarting the printer. If the light continues blinking, the network settings were likely reset. Proceed with the HP Smart app setup as described.
A solid blue Wireless light means the printer is connected. A blinking orange light indicates a wireless error or alert.