Security software frequently misidentifies compressed update packages as potential threats, cutting off the connection. Open the Start menu, type , and open it. Click on Firewall & network protection . Click Allow an app through firewall . Select Change settings (requires admin rights).
Which are you currently using? (Official, CurseForge, Prism, etc.) Minecraft Error 437 Download UPD
Your router or ISP is blocking the specific ports required by the launcher. Step-by-Step Fixes for Error 437 Minecraft Error 437 Download UPD