diff --git a/matemat/webserver/pagelets/signup.py b/matemat/webserver/pagelets/signup.py
index 99f19e0..d1bb453 100644
--- a/matemat/webserver/pagelets/signup.py
+++ b/matemat/webserver/pagelets/signup.py
@@ -70,7 +70,8 @@ def signup():
     elif request.method != 'GET':
         abort(405, 'Method not allowed')
 
-    acl = netaddr.IPSet([addr.strip() for addr in config.get('SignupKioskMode', '').split(',')])
+    acl_addrs = [s.strip() for s in config.get('SignupKioskMode', '').split(',') if s.strip()]
+    acl = netaddr.IPSet(acl_addrs)
     if request.remote_addr in acl:
         return template.render('signup_kiosk.html',
                                signup=(config.get('SignupEnabled', '0') == '1'),
diff --git a/matemat/webserver/template/template.py b/matemat/webserver/template/template.py
index f9bbf4b..ba116f4 100644
--- a/matemat/webserver/template/template.py
+++ b/matemat/webserver/template/template.py
@@ -29,7 +29,8 @@ def render(name: str, **kwargs):
     global __jinja_env
     config = get_app_config()
     template: jinja2.Template = __jinja_env.get_template(name)
-    wsacl = netaddr.IPSet([addr.strip() for addr in config.get('BarcodeWebsocketAcl', '').split(',')])
+    wsacl_addrs = [s.strip() for s in config.get('BarcodeWebsocketAcl', '').split(',') if s.strip()]
+    wsacl = netaddr.IPSet(wsacl_addrs)
     if config.get('BarcodeWebsocketUrl', '') and hasattr(request, 'remote_addr') and request.remote_addr in wsacl:
         bcwebsocket = config.get('BarcodeWebsocketUrl')
     else: