No unsafe mode available for Java/UPS.com thermal printer

After updating to MacOS Sierra, we are now not able to use our thermal printer, for printing UPS shipping labels.

Once we are at the point of printing, clicking the button brings up a pop-up window(as per usual), which gives us a selection of printers to use. Our thermal printer is always the selected option and clicking "Print", brings up a warning box...

"Thermal printing has become disabled by a browser security enhancement. You may be able to re-enable printing by authorizing UPS.com to run with full permissions. In the Safari browser, select Safari -> Preferences -> Manage Website Settings -> Java. Then select to allow UPS.com to run in Unsafe Mode. Click "Trust" when prompted."

These are obvious tasks, which didn't help, as there is no Unsafe Mode available for UPS.com on the Java section. The only options are On, Off, Ask.

We have spoken to UPS, who were no help and then went to Apple themselves. The Apple customer support person shared our screen and yet could not figure it out, as they were able to see Unsafe Mode on their own Mac, but not ours.

Of course this may nit have anything to do with updating to Sierra, but it was working perfectly before the change.

We have a backup from the beginning of the month, which we are happy to try, but something simple is wrong we feel and not worth back tracking yet...I think...

Any ideas, please?