diff --git a/data/conf/nginx/templates/sogo.auth_request.template.sh b/data/conf/nginx/templates/sogo.auth_request.template.sh
index 3139d5f8..1a7b3f72 100644
--- a/data/conf/nginx/templates/sogo.auth_request.template.sh
+++ b/data/conf/nginx/templates/sogo.auth_request.template.sh
@@ -1,6 +1,5 @@
-if printf "%s\n" "${ALLOW_ADMIN_EMAIL_LOGIN}" | grep -E '^([yY][eE][sS]|[yY])+$' >/dev/null; then
-    echo '
-auth_request /sogo-auth-verify;
+if [[ "${ALLOW_ADMIN_EMAIL_LOGIN}" =~ ^([yY][eE][sS]|[yY])+$ ]]; then
+    echo 'auth_request /sogo-auth-verify;
 auth_request_set $user $upstream_http_x_username;
 proxy_set_header x-webobjects-remote-user $user;
 '