Single page breaks site

Hi,

Just installed.

First, I add all my categories into a page: https://www.skarpekniver.com/kniv-info/sporsmal-og-svar-om-kjokkenkniver/

This works perfectly.

Then I tri to view an entry as a single page:
https://www.skarpekniver.com/kniv-info/sporsmal-og-svar-om-kniver/hva-er-en-deba/
https://www.skarpekniver.com/kniv-info/sporsmal-og-svar-om-kniver/hva-er-en-santoku/
https://www.skarpekniver.com/kniv-info/sporsmal-og-svar-om-kniver/er-det-kniver-venstrehendte/

All fail for some reason. Anyone had this problem? Anyone know what is wrong?

Best regards,
Alexander

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