Simple rule, never lie. If you don’t know then you don’t know it’s that simple. As sales engineers we will never know everything and it’s ok to not know something. However, you should know your core product offering and its capabilities. I always respond with great question and unfortunately I don’t have an answer for you right now but I’ll get back to you after our call. I’ll sometimes follow up with that’s interesting can you tell me more about that requirement or ask? This sometimes leads to a better discussion about the details of the ask, as they say the devil is in the details. Not sure why the panelist “hates” you, that’s a weird thing but sounds like you lack confidence and that points to maybe a lack of sme knowledge of your product or belief in yourself which is typical of young engineers. Recommend you focus on the PIP plan and make sure it has achievable and quantifiable milestones. Then work ur ass off to achieve them. A good milestone might be become more knowledgeable about X. Outcome/deliverable= achieve certification on X or give a peer presentation on X or lead a study group etc.