diff --git a/vm.py b/vm.py
index f958b63..8faaff0 100755
--- a/vm.py
+++ b/vm.py
@@ -25,6 +25,8 @@ import socket
 import jinja2
 import libvirt
 import ovhtool
+import ovh
+import ovh.exceptions
 
 config = {
     'vg': '/dev/vg',
@@ -240,6 +242,21 @@ def main(gargv):
 if __name__ == '__main__':
     try:
         exit(main(sys.argv[1:]))
+    except ovh.exceptions.InvalidCredential:
+        req = ovh.Client().request_consumerkey([
+            {'method': 'GET', 'path': '/ip'},
+            {'method': 'GET', 'path': '/dedicated/server'},
+            {'method': 'GET', 'path': '/dedicated/server/*/virtualMac'},
+            {'method': 'GET', 'path': '/dedicated/server/*/virtualMac/*/virtualAddress'},
+
+            {'method': 'POST', 'path': '/dedicated/server/*/virtualMac'},
+            ])
+
+        print('********\n\tNo valid OVH consumer_key, click this URL:\n\t'
+              '{0.validationUrl}\n\tand copy this consumer_key to ovh.conf: '
+              '{0.consumerKey}\n********'.format(req), file=sys.stderr)
+        exit(1)
+
     except CommandException as exc:
         print(exc, file=sys.stderr)
         exit(1)