this is just a warning and not fatal

cli/src/main/java/hudson/cli/CLI.java

@@ -488,7 +488,7 @@ public class CLI {
                         LOGGER.log(FINE,e.getMessage(),e);
                         return -1;
                     }
-                    System.err.println("Failed to authenticate with your SSH keys.");
+                    System.err.println("[WARN] Failed to authenticate with your SSH keys. Proceeding as anonymous");
                     LOGGER.log(FINE,"Failed to authenticate with your SSH keys.",e);
                 }
             }