The kind of childhood you had, past traumas, recent experiences of failure or rejection, loneliness, social anxiety, negative beliefs about yourself, perfectionism, or having a critical parent or partner can all contribute to insecurity.
People feel insecure because of judgement from themselves and others. Traumatic event of their life, or Perfectionism. Sometimes people wants to please everyone which would be a bit hard for them and if they failed themselves or everyone they starts to have a low self-esteem because they think that they are being laughed at or mock by others.
