diff --git a/app/accept_invite/rest.py b/app/accept_invite/rest.py
index bebc41b76..f7c552d34 100644
--- a/app/accept_invite/rest.py
+++ b/app/accept_invite/rest.py
@@ -34,7 +34,8 @@ def get_invited_user_by_token(token):
                                       max_age_seconds)
     except SignatureExpired:
         errors = {'invitation':
-                  ['Your invitation to GOV.UK Notify has expired. Please ask the person that invited you to send you another one']}
+                  ['Your invitation to GOV.UK Notify has expired. '
+                   'Please ask the person that invited you to send you another one']}
         raise InvalidRequest(errors, status_code=400)
 
     invited_user = get_invited_user_by_id(invited_user_id)
diff --git a/tests/app/accept_invite/test_accept_invite_rest.py b/tests/app/accept_invite/test_accept_invite_rest.py
index 94603bb69..3fbc80079 100644
--- a/tests/app/accept_invite/test_accept_invite_rest.py
+++ b/tests/app/accept_invite/test_accept_invite_rest.py
@@ -20,7 +20,8 @@ def test_accept_invite_for_expired_token_returns_400(notify_api, sample_invited_
         json_resp = json.loads(response.get_data(as_text=True))
         assert json_resp['result'] == 'error'
         assert json_resp['message'] == {'invitation': [
-            'This invitation has expired please contact the person that invited you to invite you again']}
+            'Your invitation to GOV.UK Notify has expired. '
+            'Please ask the person that invited you to send you another one']}
 
 
 def test_accept_invite_returns_200_when_token_valid(notify_api, sample_invited_user):