Avtar not starting with the KnowledgeId while starting the session

When we start to create avatar request, I try pass the "knowledgeId" . The avatar session is started but it does not start with the the prompt that we have set it in heygen labs. Please advice how to configure the avatar with the prompt when the session is started. Below is the request.

avatar.current.createStartAvatar({
quality: AvatarQuality.Medium,
avatarName: avatarId,
knowledgeId: knowledgeId,
voice: {
rate: 1.5,
emotion: VoiceEmotion.EXCITED,
},
language: language,
disableIdleTimeout: false
});