Show error message when Session failed to start

src/base/exceptions.cpp

@@ -30,11 +30,10 @@
 
 RuntimeError::RuntimeError(const QString &message)
     : std::runtime_error {message.toUtf8().data()}
-    , m_message {message}
 {
 }
 
 QString RuntimeError::message() const
 {
-    return m_message;
+    return what();
 }