Images keep returning errors

After trying to generate images of the historic figure, Nikola Tesla, I received a few guidelines errors. Once I switched the subject to generic terms like "inventions", I receive all errors and cannot generate anything new, even with new prompts. It seems like the engine took the input of "Tesla" (assuming that's the guideline issue) and is continuing to factor it into my prompts. I'm not sure if this is how Firefly works, but if so, is there a way to reset, so it discards previous prompt learning?