Dell 2155cdn network printer offline following DNS modification in web config

Hi all,

We have a Dell network printer on the wifi at the office and were having some issues with sending scanned documents by email (SMTP error). I was therefore trying to debug the problem using the Configuration Web Tool (at the printer's IP address) and I changed the setting under Printer server Settings > TCP/IP > DNS to manual from 'Get DNS Server Address from DHCP'.

However, this caused the printer to restart and go offline, and I can no longer access the web interface to change the DNS option back as it was!

Any suggestions? The printer does not seem to on the wifi at all, it is not merely that its IP address has changed (that has happened quite a few times in the past).

Is there a way to access the configurations and reset the DNS option while the printer remains offline?

Cheers,

Emilia