Had the same problem.
The secret token has changed.
Go to the code tab of the rule and find and replace the line with “var X_SECRET=” to:
var X_SECRET = "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";
here is some more info how to find the new secret if it should change:
Works for me. I hope it also does work for you.
@Mherwege maybe you can update the template with this new secret?