Why don't guys at school like me, but other places they do?

I was online for a while for school and guys would text me saying im cute on instagram, but as soon as I went to school in person its like no dude would even bother speaking to me. I get people looking at me in hallways but I think its because I dress how i want to dress and not like everyone else.
Why don't guys at school like me, but other places they do?
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