I want to talk to him

Some back story — my ex (domino 23M) and I (18F) had a baby this year but some stuff happened that is traumatic on both sides and we separated and he so far wants nothing to do with our baby. I love him still and miss him and we broke up (dated from jan./feb. 2024 - may 2024) early in my pregnancy and never married. Now we have to work out paternity and such. I tried communicating and talking to him so much to no response; I don’t understand why we can’t just talk. I have his number and the ability to message him but now it’s becoming a legal matter and my son will always be my first priority. I want to keep trying and talk to him and update him and try everything I can before it’s too late… but he’s a ghost. It already feels too late tbh and I hate it. I loved him so much and I still feel so much care and love in my heart for him that it hurts. I became 18 in March 2024 and found out about the pregnancy in April.. my baby was born Dec. 05 2024. What should I do? If I message him will it be harassment? Can I talk to him? Should I ask my attorney? What is okay in this situation?