It's not an exact science, but did you try the suggestion on first page?
"Instead of going to an HTTPS page from the HTTP page, start out in the HTTPS pages.
Example: Normally, you would go to http://xxx.xxx.xxx.xxx to access your printer's web interface, and then you click the link to one of the HTTPS pages.
Try this: Go to httpS://xxx.xxx.xxx.xxx (capitalized only for effect). This will bring you to the homepage of the printer, but there won't be any information on it. Click the Settings Tab, and then the Security link. You will be brought to a screen to create a password for the Admin account for the SSL pages. Once you've created this password, it will all work the way it's supposed to."
And the post that follows that suggests to refresh the page multiple times if that doesn't work.