How can I get my daughter to go to school without throwing a fit?p

My daughter is 4 and is preschool. Her father and I have not been together for 2 years. She went to school last year and was fine at drop off. Her father was not involved at all. This year at drop off she throws a huge fit crying and screaming, but under it she is smiling. Her father is way involved this year and likes to tell her our adult problems. I’m not sure if the two are related or not. I am just looking for advice on how to get her to let me leave her at school without throwing a huge fit. I have tried making deals with her, talking to her the night before, talking to her that morning, everything. Any advice would be awesome. Thank you.