If you are trying to (e.g., for fastboot oem unlock ), that process is typically free and official from the manufacturer (like Google Pixel, OnePlus, or Xiaomi), but requires enabling Developer Options → OEM unlocking. No Bitly link is needed.
: Bitly may block links that are reported as suspect or lead to known malicious pages. How to Safely Enable OEM Unlocking (Free) bitly oemunlock free
