Mobile Printing & Cloud Printing

My printer wont connect to the network any more. 

I select the Wireless Setup Wizard, it scans and picks up my wireless network, then asks me to enter my WPA/WEP key. I have entered it multiple times, but each time I get the error message "Invalid Wireless Password".

I am not a cabbage, I have checked multiple times that the password is keyed correctly, with correct upper case and lower case letters, no spacing at the start of the key (as was suggested in a previous solution) and it still will not register. 

I have rebooted both the printer and the router with no success. 

I have reset the printer to factory settings with no success. 

I have reset the network password to a new one (zzzzzzzz - it is the fastest one to key into the printer)  and keyed that with no success.

I have 5 other devices on the network that all connect without issue, and have previously had this printer connected to the network, until today when it decided to reject the password. 

I have changed the router settings to unsecured, but the printer still asks for a WPA code, even after another reset. 

My router only has the option for WPA2 or unsecured, however previously this printer has connected without issue. 

There is no option to update the firmware on the printer, I assume because it is not connected to a network. 

The Wireless button is a flashing blue light. Each time I try connect, it tells me the password is invalid, then turns the Wifi off wether I select "reset settings to default" or not. 

I have updated the driver on my computer (even though this is unrelated to the issue)

I need to know why the printer will not accept a WPA password any more. 

Please help.

(And if anyone suggests I need to do a recovery of my OS, I will suggest you need to re-think your career)