This usually means the developer verification state is stuck or incomplete on Meta’s backend.
Try checking bot your account settings and your developer settings as sometimes you still need to:
- Accept Developer Terms
- Verify identity
- Complete business verification prompts
Also if nothing is working, I am not sure where you are located or if this might help but try:
- Disabling any VPN
- Try another browser/device
- Wait 24h after enabling 2FA/payment methods
If it still fails, this typically requires Meta support to manually reset the developer activation state, and you can contact them through https://developers.facebook.com/support/