When my bf introduces me to his friends

Every time my bf introduces me to his guy friends,

They all act weird around me. They don’t make eye contact with me or really talk to me. They just say “nice to meet you” and that’s all.

They don’t ask me anything or make conversation. They just talk to my bf and that’s all.

It makes me feel like they don’t like me or there is something wrong with me.

Age group of these guys : 27 yrs - 60yrs. Different ages.