diff --git a/nixos/modules/services/misc/taskserver.nix b/nixos/modules/services/misc/taskserver.nix
index 7e67f2f6232..b25447ccd9d 100644
--- a/nixos/modules/services/misc/taskserver.nix
+++ b/nixos/modules/services/misc/taskserver.nix
@@ -308,7 +308,7 @@ in {
             --bits 2048 \
             --outfile "${cfg.dataDir}/keys/server.key"
 
-          ${pkgs.gnutls}/bin/certtool -s \
+          ${pkgs.gnutls}/bin/certtool -c \
             --template "${pkgs.writeText "taskserver-cert.template" ''
               cn = ${cfg.server.fqdn}
               tls_www_server