Sorry to hear about your situation.
The other advice about i) protecting your interests in the face of dubious communication, and ii) starting to look elsewhere regardless, are good. But I'd add another dimension:
Are you struggling? If yes, are you marketing your achievements enough? If not, what help do you need to get onto the right track?
The tenure-track stage is hard, for many reasons. Many people take a while to find their sea-legs, or are thrown off kilter by unrelated life complexities. Some discover being a standalone researcher is not their thing. (And some get chewed up by the tenure machine unfairly, too.) Are you making the type of progress you need, given your stage in your career?
If yes, it is unfortunately possible that your chair has it in for you and just wants to get rid of you. It is also possible your chair is just misinformed. Have you filled in requested updates in a timely fashion and highlighting your achievements? Have you communicated your research plan enough? A number of years back, a couple of us (in math) had to step in to help a brilliant but very introverted young colleague who had recently had some pretty impressive research results, had just submitted a paper about them to a prestigious journal, but filled in his activity reports -- quite accurately -- that he had published no papers and made no conference presentations, for the 3rd year in a row. He just missed the memo that self-marketing was needed.
If you've had setbacks that have impacted your progress, but are now on track, do you have your narrative ready about that. Research often doesn't work the way it should; experiments fail; hypotheses turn our wrong; ethics committees misunderstand and delay progress. We, as lonely academics, get sick, depressed, etc. Too often we try to internalize all these wounds, since they make us feel vulnerable. But do they in fact explain limitations you have had that may be giving a wrong impression as to your future promise in a research career?
If you are struggling now, but do want to continue, what help do you need? Do you have mentors to guide you? Do you need specific support to get over roadblocks? If you are having some personal challenges, look into (and definitely ask your union) what are accommodations that you may be entitled to. In my old department, there was very little attention paid to such things. My wife's department has a pretty extensive accommodation policy, for both students and faculty, that in particular has helped some of her junior colleagues by "pausing the tenure clock" when needed, or considering progress in context. But you have to know to ask, especially if your chair seems at best clueless.
All of this is both to get you into a better place, if needed; and to take charge of the narrative, if you've let it run away from you. It's also helpful to think through if it is true the chair just has it in for you...since then, part of your response is to make it clear you are informed, equipped with facts/narrative of your own, and therefore not an attractive expendable target, if there is funny business going on.
Good luck!
