unsuccessful(unstable and dirty) proxy solution

public/js/index.js

@@ -1,5 +1,9 @@
 window.onload = async () => {
     let id = (await (await fetch("/api/captcha", {method: "POST"})).json()).id
+    if (id == undefined) {
+        alert("Service is unavailable now. Please, try again later.");
+        return;
+    }
     console.log(id);
     fetch(`/api/captcha/${id}`).then(response => response.blob())
         .then(blob => {