diff --git a/contrib/buildbot/server.py b/contrib/buildbot/server.py
--- a/contrib/buildbot/server.py
+++ b/contrib/buildbot/server.py
@@ -175,7 +175,7 @@
     @app.route("/build", methods=['POST'])
     def build():
         buildTypeId = request.args.get('buildTypeId', None)
-        ref = request.args.get('ref', 'master')
+        ref = request.args.get('ref', 'refs/heads/master')
 
         PHID = request.args.get('PHID', None)
 
@@ -283,7 +283,7 @@
         }]
         output = tc.trigger_build(
             LANDBOT_BUILD_TYPE,
-            'master',
+            'refs/heads/master',
             UNRESOLVED,
             properties)
         if output:
diff --git a/contrib/buildbot/test/test_endpoint_build.py b/contrib/buildbot/test/test_endpoint_build.py
--- a/contrib/buildbot/test/test_endpoint_build.py
+++ b/contrib/buildbot/test/test_endpoint_build.py
@@ -16,7 +16,6 @@
 class buildRequestQuery():
     def __init__(self):
         self.buildTypeId = 'test-build-type-id'
-        self.ref = 'refs/heads/master'
         self.PHID = 'buildPHID'
 
     def __str__(self):
diff --git a/contrib/buildbot/test/test_endpoint_land.py b/contrib/buildbot/test/test_endpoint_land.py
--- a/contrib/buildbot/test/test_endpoint_land.py
+++ b/contrib/buildbot/test/test_endpoint_land.py
@@ -32,7 +32,7 @@
         self.teamcity.session.send.assert_called_with(AnyWith(requests.PreparedRequest, {
             'url': 'https://teamcity.test/app/rest/buildQueue',
             'body': json.dumps({
-                'branchName': 'master',
+                'branchName': 'refs/heads/master',
                 'buildType': {
                     'id': 'BitcoinAbcLandBot',
                 },