diff --git a/api/netdiag_api.lib.php b/api/netdiag_api.lib.php
index d69af0b..87666b0 100644
--- a/api/netdiag_api.lib.php
+++ b/api/netdiag_api.lib.php
@@ -298,6 +298,28 @@ function netdiag_api_read_body()
 	return is_array($data) ? $data : array();
 }
 
+/**
+ * Zeitstempel der App in einen Unix-Zeitstempel (Sekunden) umrechnen.
+ *
+ * Die App (JavaScript) liefert Zeitstempel in Millisekunden (Date.now()).
+ * Dolibarr/`idate()` erwartet Sekunden — sonst: "Bad value ... for date".
+ *
+ * @param  mixed $value Zeitstempel aus dem Request (ms, s oder leer)
+ * @return int          Unix-Zeitstempel in Sekunden
+ */
+function netdiag_api_timestamp($value)
+{
+	$v = (int) $value;
+	if ($v <= 0) {
+		return dol_now();
+	}
+	// 13-stellig (> ~Jahr 5138 in Sekunden) = Millisekunden -> auf Sekunden
+	if ($v > 100000000000) {
+		$v = (int) ($v / 1000);
+	}
+	return $v;
+}
+
 /**
  * Liste von Diagnose-Protokollen als Array zurückgeben (für API-Antworten).
  *
diff --git a/api/protocols.php b/api/protocols.php
index cf6575b..f6e2a83 100644
--- a/api/protocols.php
+++ b/api/protocols.php
@@ -134,7 +134,7 @@ $protocol->client_uuid       = $uuid;
 $protocol->label             = isset($p['label']) ? (string) $p['label'] : '';
 $protocol->fk_soc            = !empty($p['socId']) ? (int) $p['socId'] : null;
 $protocol->fk_commande       = !empty($p['orderId']) ? (int) $p['orderId'] : null;
-$protocol->date_diag         = !empty($p['dateDiag']) ? (int) $p['dateDiag'] : dol_now();
+$protocol->date_diag         = netdiag_api_timestamp($p['dateDiag'] ?? 0);
 $protocol->fk_user_techniker = (int) $user->id;
 $protocol->standort          = isset($p['location']) ? (string) $p['location'] : '';
 $protocol->subnet            = isset($p['subnet']) ? (string) $p['subnet'] : '';
@@ -194,7 +194,7 @@ foreach ($measIn as $m) {
 	$meas->params        = isset($m['params']) ? json_encode($m['params'], JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES) : null;
 	$meas->result        = isset($m['result']) ? json_encode($m['result'], JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES) : null;
 	$meas->measure_status = isset($m['measureStatus']) ? (int) $m['measureStatus'] : 0;
-	$meas->date_measure  = !empty($m['dateMeasure']) ? (int) $m['dateMeasure'] : dol_now();
+	$meas->date_measure  = netdiag_api_timestamp($m['dateMeasure'] ?? 0);
 	$meas->tms           = dol_now();
 	if ($meas->create($user, 1) <= 0) {
 		$db->rollback();