S.K.
I have to agree with everyone else. As a provider myself, it's hard to watch the parents struggle with this. The children usually are not struggling the way the parents think. They are momentarily unhappy they are switching from mom to daycare. The same child is just as likely to go through spells where they are throwing these tantrums when leaving daycare at the end of the day. Sometimes it's separation anxiety. Sometimes it's a control thing. Sometimes it's them having a problem with transitions in general. For instance, if you've ever been playing at the park and the child doesn't want to leave, it's the same. Or if you are coloring and it's time to put the crayons away and some children will throw a fit about that. Even if the next activity or person they are changing to is something or someone they love dearly, it's hard to switch.
Hang in there. It will get better.
One thing though, I missed the age of the child. Sometimes another child does something mean and that can make a child not want to come for awhile. I've had to face these situations rather helplessly through the years when some child had one bad experience and forever disliked us all because of it. It's one reason I am very concerned about behavior and training the children to care for each other. I believe in very active supervision so that I can try my best to keep things from happening.