diff --git a/intelmq/lib/mixins/http.py b/intelmq/lib/mixins/http.py
index 6a6befb96..24ef4f2d1 100644
--- a/intelmq/lib/mixins/http.py
+++ b/intelmq/lib/mixins/http.py
@@ -50,7 +50,6 @@ class HttpMixin:
 
     def __init__(self, **kwargs):
         self.logger.debug("Running HTTP Mixin initialization.")
-        self.http_header = {}
         super().__init__()
 
     def setup(self):
@@ -70,9 +69,9 @@ def setup(self):
             self.__auth = (self.http_username, self.http_password)
         self.__session.auth = self.__auth
         # headers settings
-        if self.http_header is not None:
+        if self.http_header:
             self.__session.headers.update(self.http_header)
-        elif self.http_user_agent is not None:
+        if self.http_user_agent:
             self.__session.headers.update({"User-Agent": self.http_user_agent})
 
         # proxy settings