diff --git a/netx_api/main.py b/netx_api/main.py
index ce5e889..eaebd12 100644
--- a/netx_api/main.py
+++ b/netx_api/main.py
@@ -815,9 +815,23 @@ def on_startup() -> None:
             last_error=f"startup_thread_init_failed: {str(exc)[:180]}",
         )
     try:
-        _run_startup_alarm_sync_before_ws()
+
+        def _startup_alarm_sync_worker() -> None:
+            try:
+                _run_startup_alarm_sync_before_ws()
+            except Exception as exc:
+                _schedule_log.exception("startup: alarm sync before WSS failed: %s", exc)
+                complete_startup_alarm_sync_gate()
+
+        # Do not block HTTP /health on slow UME REST pull; WSS waits on startup_alarm_sync_gate.
+        t_startup_sync = threading.Thread(
+            target=_startup_alarm_sync_worker,
+            name="ume-startup-alarm-sync",
+            daemon=True,
+        )
+        t_startup_sync.start()
     except Exception as exc:
-        _schedule_log.exception("startup: alarm sync before WSS failed: %s", exc)
+        _schedule_log.exception("startup: alarm sync thread init failed: %s", exc)
         complete_startup_alarm_sync_gate()
     try:
         if bool(getattr(settings, "ume_sync_alarms_current_enabled", True)):
diff --git a/scripts/start_netx.ps1 b/scripts/start_netx.ps1
index 6bb4c60..f49d41d 100644
--- a/scripts/start_netx.ps1
+++ b/scripts/start_netx.ps1
@@ -93,7 +93,7 @@ function Show-LogTail {
 }
 
 function Test-NetxApiListening {
-    param([string]$HostName, [int]$LocalPort, [int]$WaitSec = 12)
+    param([string]$HostName, [int]$LocalPort, [int]$WaitSec = 45)
     $deadline = (Get-Date).AddSeconds($WaitSec)
     while ((Get-Date) -lt $deadline) {
         try {
@@ -135,8 +135,9 @@ if ($Background) {
         Show-LogTail -Path $logFile
         exit 1
     }
-    if (-not (Test-NetxApiListening -HostName $BindHost -LocalPort $Port)) {
-        Write-Host "[ERR] Port $Port not listening /health not OK within 12s (PID may still be starting or stuck on DB)." -ForegroundColor Red
+    $healthWaitSec = 45
+    if (-not (Test-NetxApiListening -HostName $BindHost -LocalPort $Port -WaitSec $healthWaitSec)) {
+        Write-Host "[ERR] Port $Port not listening /health not OK within ${healthWaitSec}s (process may be stuck on DB or schema migration)." -ForegroundColor Red
         Show-LogTail -Path $errFile
         Show-LogTail -Path $logFile
         exit 1