The Quick Answer
If your HP LaserJet M209dwe keeps going offline, it is likely due to your router assigning a new IP address to the printer after a reboot or lease expiration. To fix this permanently, log into your router and assign a Static IP Address to the printer's MAC address.
The Root Cause of "Offline" Status
The M209dwe is an HP+ printer, which means it relies heavily on a continuous network connection. When your computer says the printer is offline, it simply means the computer is sending data to the old IP address, but the printer is now residing at a new IP address.
The Permanent Fix: Assigning a Static IP
By assigning a static IP, you tell your router to never change the printer's address.
- Print a Network Configuration Page: Press and hold the Information button (i) on the printer until all buttons light up, then press the Information button and the Resume button at the same time.
- Find the IP Address: Look at the printed page to find the current IPv4 address (e.g., 192.168.1.15).
- Access the EWS: Type that IP address directly into a web browser on your computer.
- Navigate to Network Settings: Go to the Network tab > IPv4 Configuration.
- Set to Manual IP: Change the IP assignment from Automatic (DHCP) to Manual (Static). Input an IP address outside of your router's normal DHCP range (e.g., if your DHCP range is .2 to .100, set the printer to .200). Save the settings.
HP+ Internet Requirements
Remember that the "e" at the end of M209dwe stands for HP+. This means the printer must have access to the internet. If you have blocked the printer in your router firewall, or if your internet goes down, the printer will refuse to print, even over a local USB connection.
