People keep telling me I seem like I don't like them and I don't know how to fix it.

I have had multiple people tell me that they feel disliked by me. Coworkers, acquaintances, even a friend's partner. They say I come across as cold or dismissive. The thing is, I don't dislike these people. I just don't always know what to say or how to show that I care. I think I am being neutral or even friendly, but apparently it reads as rejection.

I have tried masking harder and forcing more enthusiasm, but that just drains me completely. I also don't want to lie about my feelings. At the same time, I don't want to make other people feel bad. It is exhausting to constantly manage how I am being perceived on top of everything else.

Does anyone else deal with this? How do you handle it when people assume you don't like them? Do you explain that you are autistic and that your affect is flat, or do you just let them think what they want? I don't want to use my diagnosis as an excuse, but I also feel like I am being judged for something I cannot really change. I would love to hear what has worked for other people in work and social settings.