If Sol is treating you like a new user when you expected him to remember you, there are a few possible explanations - most of which are straightforward to resolve.

Sol's memory only works when you're signed in to your account. If you're not signed in, Sol has no access to your memory summary and will treat you as an anonymous user.

Sol draws on his memory to shape how he listens - but he doesn't open every conversation by announcing what he knows. His memory shapes the conversation without leading it. Try mentioning something from your previous conversations and see whether Sol recognises it.