diff --git a/launcher/minecraft/MinecraftInstance.cpp b/launcher/minecraft/MinecraftInstance.cpp
index 68629ff42..d43ffe2e4 100644
--- a/launcher/minecraft/MinecraftInstance.cpp
+++ b/launcher/minecraft/MinecraftInstance.cpp
@@ -569,6 +569,14 @@ QStringList MinecraftInstance::processAuthArgs(AuthSessionPtr session) const
                 break;
             }
         }
+    } else if (session->wants_online && (v == "1.16.4" || v == "1.16.5")) {
+        // https://github.com/FabricMC/fabric-loom/issues/915#issuecomment-1609154390
+        QString invalid_url{ "https://invalid.invalid" };
+        args << "-Dminecraft.api.env=custom";
+        args << "-Dminecraft.api.auth.host=" + invalid_url;
+        args << "-Dminecraft.api.account.host=" + invalid_url;
+        args << "-Dminecraft.api.session.host=" + invalid_url;
+        args << "-Dminecraft.api.services.host=" + invalid_url;
     }
     return args;
 }
diff --git a/launcher/minecraft/auth/AuthSession.cpp b/launcher/minecraft/auth/AuthSession.cpp
index 37534f983..f169eb834 100644
--- a/launcher/minecraft/auth/AuthSession.cpp
+++ b/launcher/minecraft/auth/AuthSession.cpp
@@ -27,6 +27,7 @@ bool AuthSession::MakeOffline(QString offline_playername)
     access_token = "0";
     player_name = offline_playername;
     status = PlayableOffline;
+    wants_online = false;
     return true;
 }
 
diff --git a/launcher/minecraft/launch/LauncherPartLaunch.cpp b/launcher/minecraft/launch/LauncherPartLaunch.cpp
index cbd9ead67..d6b8d6da1 100644
--- a/launcher/minecraft/launch/LauncherPartLaunch.cpp
+++ b/launcher/minecraft/launch/LauncherPartLaunch.cpp
@@ -117,9 +117,9 @@ void LauncherPartLaunch::executeTask()
     }
 
     m_launchScript = minecraftInstance->createLaunchScript(m_session, m_serverToJoin);
-    QStringList args = minecraftInstance->javaArguments();
 
-    args.append(minecraftInstance->processAuthArgs(m_session));
+    auto args = minecraftInstance->processAuthArgs(m_session);
+    args.append(minecraftInstance->javaArguments());
 
     QString allArgs = args.join(", ");
     emit logLine("Java Arguments:\n[" + m_parent->censorPrivateInfo(allArgs) + "]\n\n", MessageLevel::Launcher);