Thanks everyone for your answers.

I actually found what it was about a while ago but forgot to post it

turned out to be a browser issue: AWS Console was showing error pop-ups, but they didn’t appear in Opera for some reason. When I switched browsers, the error messages became visible. The model i was trying to use was not supported at the time as Rag only supported Anthropic models. Also, as of August 24, they support LLaMA too! https://docs.aws.amazon.com/bedrock/latest/userguide/knowledge-base-supported.html