Possible short answer: "Have you tried using the document.cookie API or a vue-cookie package?"
Troubleshooting Tips for Setting Cookies in Vue.js
When building applications with Vue.js that require user authentication, setting cookies can be a crucial part of the process. Cookies allow for persistent authentication and can help maintain a user's session across multiple pages.
Why Your Cookie Won't Set in Your Vue.js Application: Common Causes and Solutions
How to Debug Cookie-Related Issues in Your Vue.js App