diff --git a/gns3server/handlers/api/iou_handler.py b/gns3server/handlers/api/iou_handler.py
index 5606cd8b..c828eef1 100644
--- a/gns3server/handlers/api/iou_handler.py
+++ b/gns3server/handlers/api/iou_handler.py
@@ -232,7 +232,7 @@ class IOUHandler:
         if nio_type not in ("nio_udp", "nio_tap", "nio_generic_ethernet"):
             raise HTTPConflict(text="NIO of type {} is not supported".format(nio_type))
         nio = iou_manager.create_nio(vm.iouyap_path, request.json)
-        vm.adapter_add_nio_binding(int(request.match_info["adapter_number"]), int(request.match_info["port_number"]), nio)
+        yield from vm.adapter_add_nio_binding(int(request.match_info["adapter_number"]), int(request.match_info["port_number"]), nio)
         response.set_status(201)
         response.json(nio)
 
@@ -255,7 +255,7 @@ class IOUHandler:
 
         iou_manager = IOU.instance()
         vm = iou_manager.get_vm(request.match_info["vm_id"], project_id=request.match_info["project_id"])
-        vm.adapter_remove_nio_binding(int(request.match_info["adapter_number"]), int(request.match_info["port_number"]))
+        yield from vm.adapter_remove_nio_binding(int(request.match_info["adapter_number"]), int(request.match_info["port_number"]))
         response.set_status(204)
 
     @Route.post(
diff --git a/gns3server/modules/iou/iou_vm.py b/gns3server/modules/iou/iou_vm.py
index 1fe6ace1..d6cfefa6 100644
--- a/gns3server/modules/iou/iou_vm.py
+++ b/gns3server/modules/iou/iou_vm.py
@@ -912,6 +912,7 @@ class IOUVM(BaseVM):
 
         self._adapters = self._ethernet_adapters + self._serial_adapters
 
+    @asyncio.coroutine
     def adapter_add_nio_binding(self, adapter_number, port_number, nio):
         """
         Adds a adapter NIO binding.
@@ -944,6 +945,7 @@ class IOUVM(BaseVM):
             except ProcessLookupError:
                 log.error("Could not update iouyap configuration: process (PID={}) not found".format(self._iouyap_process.pid))
 
+    @asyncio.coroutine
     def adapter_remove_nio_binding(self, adapter_number, port_number):
         """
         Removes an adapter NIO binding.
diff --git a/tests/modules/iou/test_iou_vm.py b/tests/modules/iou/test_iou_vm.py
index 6a4503ea..4d0e48ec 100644
--- a/tests/modules/iou/test_iou_vm.py
+++ b/tests/modules/iou/test_iou_vm.py
@@ -341,7 +341,7 @@ def test_start_capture(vm, tmpdir, manager, free_console_port, loop):
 
     output_file = str(tmpdir / "test.pcap")
     nio = manager.create_nio(vm.iouyap_path, {"type": "nio_udp", "lport": free_console_port, "rport": free_console_port, "rhost": "127.0.0.1"})
-    vm.adapter_add_nio_binding(0, 0, nio)
+    loop.run_until_complete(asyncio.async(vm.adapter_add_nio_binding(0, 0, nio)))
     loop.run_until_complete(asyncio.async(vm.start_capture(0, 0, output_file)))
     assert vm._adapters[0].get_nio(0).capturing
 
@@ -350,7 +350,7 @@ def test_stop_capture(vm, tmpdir, manager, free_console_port, loop):
 
     output_file = str(tmpdir / "test.pcap")
     nio = manager.create_nio(vm.iouyap_path, {"type": "nio_udp", "lport": free_console_port, "rport": free_console_port, "rhost": "127.0.0.1"})
-    vm.adapter_add_nio_binding(0, 0, nio)
+    loop.run_until_complete(asyncio.async(vm.adapter_add_nio_binding(0, 0, nio)))
     loop.run_until_complete(vm.start_capture(0, 0, output_file))
     assert vm._adapters[0].get_nio(0).capturing
     loop.run_until_complete(asyncio.async(vm.stop_capture(0, 0)))