Hi pixel_perfect,

Does the error occur right after pressing register and the spinning circles spin, stop and then the program freezes? If so can you follow the instructions below to see if that fixes it for you.
The solution is to reset the "Internet Explorer" settings.
1.Open the "Internet Explorer" (not Edge)
2.Click the Tools button Tools, and then click Internet options.
3.Click the "Advanced" tab, click "Restore advanced settings" and then click "Reset".
4.In the Reset Internet Explorer Settings dialog box, click Reset.
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5.Click the "Security" tab, then click "Custom Level..." and then click "Reset".
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6.When Internet Explorer finishes applying default settings, click Close, and then click OK. You'll need to restart your PC for these changes to take effect.

7.Now try to activate again, this time it should work.

Thanks,
Ben