diff --git a/src/ATBAPP/DeviceControllerDiag.cpp b/src/ATBAPP/DeviceControllerDiag.cpp
index 1bcac63..6ec95ae 100644
--- a/src/ATBAPP/DeviceControllerDiag.cpp
+++ b/src/ATBAPP/DeviceControllerDiag.cpp
@@ -104,6 +104,14 @@ void DeviceControllerDiag::private_startDiag()
         this->private_sendDiagEvent(DeviceController::State::E255);
         this->isRequestRunning  = false;
         this->flagInterruptDiag = false;
+
+        // try it again, until success:
+        QTimer::singleShot(400, this, &DeviceControllerDiag::diagRequest);
+        /**
+         * But please note:
+         * - diag does currently not stop suspend (start a background task)
+         * - diag is called again in ModeOOO wokeup()
+         */
         return;
     }