The stored activation key is invalid

[Challa]

I get this popup when opening makemkv. I have a valid purchase registration. I bought it many years ago and never had problem until now.

Then another popup saying application version is too old. I downloaded directly from makemkv website, newest version.

[Woodstock]

Re-enter the key; the permanent keys should always work, even with old versions.

What version is displayed when MakeMKV starts up? If it is the latest, it should be 1.15.3 today.