Common reasons include:
Some or all requirements were not fully met (e.g., not reaching the required level, not completing the registration form, not keeping the app installed for the minimum time).
You used a VPN or proxy, which is often disallowed and can void the offer.
You previously completed the same offer on another site or account (many offers are “new users only”).
Tracking was blocked by your browser settings, ad blockers, or privacy tools.
The offer provider has not yet confirmed your completion (it may still be processing).