This happens sometimes even when a person has done nothing to deserve it, for intance when a popular team member leaves and you are the replacement. Firstly, consider whether any actions you have made have caused this opposition, or whether your manner has offended team members. In a meeting, without getting angry, look around people and state openly that you are aware that the team feels oppositional towards you and invite them to explain how things could be better.
Do this in a friendly and cooperative way. If someone broaches a suggestion about what you have done that has upset them, do not brush it away or angrily deny it. Listen. Thank them for having the courtesy of making a suggestion.
If you have no answer, play for time. say you have understood what they've said, you don't think this is the way you see it but you are going to go away and think about it. The main thing is to find the cause of the opposition.
Ask the team for the cause. Only when matters are in the open can you, and hopefully they, begin to repair the relationship. You all have to do this for the sake of the work in hand, something you perhaps have to say around the table.