My boyfriend's mom hates me.🙄

I haven't done anything for her to dislike me.
I've been with my boyfriend for 3 Months, and we're pretty functional together.
Don't get me wrong, we spend a lot of time together so we argue a bit, and there's times when it progresses into heated yelling at eachother but then we're good.
Well he lives with his mother for now because college and stuff and he works too.
The other day she randomly decided to tell my boyfriend that I wasn't allowed on the property anymore and that I wasn't to come over ever again. She has NO reason, i'm always super respectful and everything when im around his family. 
At my house it's really hard to have him over because she always demands him home when she knows he's with me.
What can I do?