diff --git a/daemon.py b/daemon.py
index 38da5e467..279fc6788 100644
--- a/daemon.py
+++ b/daemon.py
@@ -538,6 +538,9 @@ class PubServer(BaseHTTPRequestHandler):
     def _blockedUserAgent(self, callingDomain: str, agentStr: str) -> bool:
         """Should a GET or POST be blocked based upon its user agent?
         """
+        if not agentStr:
+            return False
+
         agentStrLower = agentStr.lower()
         defaultAgentBlocks = [
             'fedilist.com'