수정 4번째...

src/views/3_api/todo/listView.vue

@@ -112,6 +112,9 @@
 <script>
 // 참조 : https://cdmoro.github.io/bootstrap-vue-3/components/
 import axios from 'axios'
+axios.defaults.baseURL = 'http://localhost:3000'
+axios.defaults.headers.post['Content-Type'] = 'application/json;charset=utf-8'
+axios.defaults.headers.post['Access-Control-Allow-Origin'] = '*'
 export default {
   components: {},
   data() {
@@ -183,7 +186,7 @@ export default {
     async getDatas() {
       this.isBusy = true
       const items = await axios
-        .get('http://localhost:3000/todo', {
+        .get('/todo', {
           params: {
             page: parseInt(this.currentPage),
             per_page: parseInt(this.perPage),