Defensive coding

core/lookup_helper.py

@@ -455,6 +455,11 @@ class LookupHelper:
                     # QRZ had no info for the call, that's OK. Cache a None so we don't try to look this up again
                     self.QRZ_CALLSIGN_DATA_CACHE.add(call, None, expire=604800)  # 1 week in seconds
                     return None
+            except (Exception):
+                # General exception like a timeout when communicating with QRZ. Return None this time, but don't cache
+                # that, so we can try again next time.
+                logging.error("Exception when looking up QRZ data")
+                return None
         else:
             return None