我在使用twitter api时遇到问题，它会返回400个不良请求

I am having trouble accessing the twitter api. It give 400 Bad request. Previously it was giving unauthorized exception. Can someone please help me figure out what am I doing wrong? I am writing this code for image upload. I thought I would first try with regular post method then would add file upload but stuck at Bad requestI am having trouble accessing the twitter api.