1. Permission: "Mag niet" cannot be used to grant permission. For example, if you want to ask someone if you can do something, you would say "Mag ik?" which means "May I?" instead of "Mag ik niet?"
2. Requests: "Mag niet" cannot be used to make requests. For example, if you want to ask someone to do something, you would say "Wil je?" which means "Will you?" or "Kun je?" which means "Can you?" instead of "Mag je niet?"
3. Suggestions: "Mag niet" cannot be used to make suggestions. For example, if you want to suggest something to someone, you would say "Misschien," which means "Maybe" or "Ik denk dat," which means "I think" instead of "Mag je niet?"
Overall, "mag niet" is primarily used to convey prohibitions or restrictions, while expressing permission, requests, or suggestions requires different phrases in Dutch.