There is a problem with the registration code, please help, thank you

I have purchased PD16, PD16 is upgraded from PD15, but when installing PD16, you need to provide the registration code of PD15, the system prompts that the registration code of PD15 is wrong, and the content is: "Please make sure that the key entered is correct. Yours The activation key is stored in your Parallels account. If you don't want to bother memorizing a large number of activation keys and manually completing the upgrade process in the future, it is recommended to purchase a Parallels Desktop subscription."
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But I copied the registration code of PD15 from the Parallels account on the official website. There should be no errors. How can I solve it? I need help, thank you!

 

Hello, please provide us with both your keys.
We will check it for you.