https://en.wikipedia.org/wiki/Hallucination_(artificial_intelligence)
https://machinelearningmastery.com/a-gentle-introduction-to-hallucinations-in-large-language-models/
In short: Language models are not search engines or databases. They make up text. Hallucinations are unavoidable.
You can't trust them. This is still matter of research. Maybe it'll get better in a few years once researchers found good ways to mitigate this.