Are you serious? After spending the time to configure my camera with all the custom settings you're asking me to reset it back to the factory setting to see if no password will work from the WAN?
First off this will break the port forwarding as this will switch from a static IP back to DHCP so I'll have to change my router too. Then the camera will be wide open to the outside!?! And if it works without a password what does this tell us? I can't securely use the camera in this configuration and then I have to go back and configure it all again to then not have it still work!
I think you need to offer something different to try like maybe just clearing the admin password I currently have first and see if that works? I already fell into your 16 character WiFi password limit and had to change router settings to work around that. You don't have a password character limit for the accounts do you?