Is it possible that I am in a blacklist?
Yes.
Many companies track candidates and there is often a check box for "consider for other roles?" which can say either yes or no. Some companies do this, others do not.
This would depend a lot on how your last interaction went and if you manage to seriously annoy someone in the process. Personally, I prefer the decision to be mostly made before making a real offer: Creating a formal offer can take a lot of work, time and administrative effort, and I prefer not to do this if there are still open issues that can kill the deal. I would indeed be annoyed having an offer be rejected after giving the impression that everything is hunky dory. Whether that would result in blacklisting would depend very much on the details.
In any case, you will not be able to find out whether you got blacklisted and, even if you are, there is nothing you can do about it. Just keep applying, but make sure you cast your net wide enough and don't focus on a single company. Not having heard back on any application is unfortunately pretty normal these days.