If the message "You are not authorized to perform this action" appears following an attempt to perform any type of operation on the platform, your user may have access / operation restrictions configured in Security or in Dynamic security (Data access).
Make sure (or request an Administrator user in your company to verify) that your user has the necessary permissions, by checking:
- Group membership of your user:
- Click on Setup > Security > Users
- Click on the name of the user to be verified
- Check the Groups tabs
- Check which group your user belongs to (see also the Security section for more details)
- Access restrictions that may have been set for specific sections: