Fix SSH Host Key Verification Failed on Linux - How to Fix PuTTY Connection Refused on Ubuntu-How to Fix Security App Version Mismatch

Updated 2026-06-13 13:36:28windows-fixes
Fix SSH Host Key Verification Failed on Linux - How to Fix PuTTY Connection Refused on Ubuntu-How to Fix Security App Version Mismatch
Before changing system settings, save your work and note the exact error text so you can compare results after each step.

Extra verification checklist

  • Restart the affected app after changing permissions or configuration files.
  • Test the same workflow in a clean browser profile or a temporary user account.
  • Compare the result on another network if the error may be connection related.