Is it CORS?

vercel.json

@@ -1,5 +1,14 @@
 {
   "headers": [
+    {
+      "source": "/api/(.*)",
+      "headers": [
+        { "key": "Access-Control-Allow-Credentials", "value": "true" },
+        { "key": "Access-Control-Allow-Origin", "value": "*" },
+        { "key": "Access-Control-Allow-Methods", "value": "GET,OPTIONS,PATCH,DELETE,POST,PUT" },
+        { "key": "Access-Control-Allow-Headers", "value": "X-CSRF-Token, X-Requested-With, Accept, Accept-Version, Content-Length, Content-MD5, Content-Type, Date, X-Api-Version" }
+      ]
+    },
     {
       "source": "/(.*)",
       "headers": [