diff --git a/scrapyd/webservice.py b/scrapyd/webservice.py
index cbb1437e..8b0f7c51 100644
--- a/scrapyd/webservice.py
+++ b/scrapyd/webservice.py
@@ -148,6 +148,8 @@ def render_POST(self, txrequest, project, job, signal):
         if project not in self.root.poller.queues:
             raise error.Error(code=http.NOT_FOUND, message=b"project '%b' not found" % project.encode())
 
+        prevstate = None
+
         if self.root.poller.queues[project].remove(lambda x: x["_job"] == job):
             prevstate = "pending"