This guy I was talking to, but stopped, just messaged me out of blue “happy birthday”

This guy I was talking to, but stopped, just messaged me out of the blue "happy birthday" what should I do or take of that?
This guy I was talking to, but stopped, just messaged me out of the blue “happy birthday” what should I do or take of that?

I think it depends – if you are interested in chatting more with this person, you can reply something simple like “Thanks!” and if you are not interested in pursuing any sort of connection it is okay to ignore the text.