Error: Critical CSS <style> element not found

[Seek51]

Here there,

I am always getting the error:
Error: Critical CSS <style> element not found

Why this could happen?

[optimalisatie]

Hi!

The message means most likely that no critical CSS has been added yet. The critical CSS editor has a lower priority since it does work correctly besides this small user experience issue. We will improve the editor soon.

To resolve the issue, it is required to add a critical CSS file.