Getting - PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException

i am completely beginner. Inorder to get some idea knowledge graphs woks. i am doing exactly

''':play https://guides.neo4j.com/nlp_knowledge_graphs''' what this says

I am doing this Link.

when i run software systems query. i got termination status as "KO" and triples loaded is 0.

can anyone please help me here