Make sure u have enabled these permissions (delegated and application) https://graph.microsoft.com/Chat.ReadWrite https://graph.microsoft.com/ChatMember.ReadWrite https://graph.microsoft.com/User.Read https://graph.microsoft.com/TeamsAppInstallation.ReadWriteAndConsentSelfForChat.

Use a delegated access token in the add app to chat api. get the access token by doing a Oauth2.0 with your bot app . (note: dont use the bot access token which wont work in most cases).

also check if u are having any rsc permissions in your manifest.json