diff --git a/firefox/55-proxy_dns_socks5.yml b/firefox/55-proxy_dns_socks5.yml
index 55bddd3b..2dbe9d1c 100644
--- a/firefox/55-proxy_dns_socks5.yml
+++ b/firefox/55-proxy_dns_socks5.yml
@@ -7,7 +7,7 @@ proxy_dns_socks5:
   default: false
   disabled:
     jinja: |-
-      {{ _.proxy_mode != "Manual proxy configuration" or _.manual.socks_proxy.version == 'v4' }}
+      {{ _.manual.socks_proxy.version is propertyerror or _.manual.socks_proxy.version == 'v4' }}
     return_type: boolean
     description: |-
       if "_.proxy_mode" is not "Manual proxy configuration"