Parallels Desktop 13 perpetual license activation rejected

I have a perpetual license for Parallels Desktop 13. I have the original license key and it was working previously. Now activation fails with the message that the license server rejected the license. I'm using macOS High Sierra. Could you please check my license and reset the activation if necessary? The error message in Japanese is: 「ライセンスサーバーに拒否されました」 I still have the original license key.

 

The same boot disk that activates successfully on another Mac also fails when booted on this iMac Pro. Therefore the issue appears to be specific to this iMac Pro hardware.