diff --git a/gns3server/modules/qemu/qemu_vm.py b/gns3server/modules/qemu/qemu_vm.py
index 32f91768..3f186baa 100644
--- a/gns3server/modules/qemu/qemu_vm.py
+++ b/gns3server/modules/qemu/qemu_vm.py
@@ -870,7 +870,7 @@ class QemuVM(BaseVM):
                     log.error("Could not start QEMU {}: {}\n{}".format(self.qemu_path, e, stdout))
                     raise QemuError("Could not start QEMU {}: {}\n{}".format(self.qemu_path, e, stdout))
 
-                self._set_process_priority()
+                yield from self._set_process_priority()
                 if self._cpu_throttling:
                     self._set_cpu_throttling()
 
diff --git a/gns3server/server.py b/gns3server/server.py
index 0c81b5a3..c472188d 100644
--- a/gns3server/server.py
+++ b/gns3server/server.py
@@ -221,6 +221,9 @@ class Server:
             ssl_context = self._create_ssl_context(server_config)
 
         self._loop = asyncio.get_event_loop()
+        # Asyncio will raise error if coroutine is not called
+        self._loop.set_debug(True)
+
         app = aiohttp.web.Application()
         for method, route, handler in Route.get_routes():
             log.debug("Adding route: {} {}".format(method, route))