Short answer: You’ve hit a rule or a limit.
- 📈 Friend cap: Basic 50 · Premium 1000 · VIP 2000 — pending requests count.
- 🧹 Free space: remove friends or cancel pending requests.
- ↩️ Declined? You can’t resend; they must add you.
- ✉️ Message first: you can only add members who have messaged you at least once.
💡 Tip: Start a friendly chat — once they reply, you can add them.