diff --git a/src/adapter/index.js b/src/adapter/index.js
index 6b449f3b5d6e3274e9eb947db660e1b9900da008..9c1a21a9df9bf8d9cd91abeab525df75b8aca8d2 100644
--- a/src/adapter/index.js
+++ b/src/adapter/index.js
@@ -69,7 +69,7 @@ export class Adapter {
    */
   auth() {
     return this.axios
-      .get(`{this.config.api}/token`, {
+      .get(`${this.config.api}/token`, {
         params: {
           client_id: this.config.client_id,
           secret: this.config.secret,
@@ -90,7 +90,7 @@ export class Adapter {
   poll() {
     return this.getAuthorizationHeader()
       .then((headers) => {
-        return this.axios.get(`{this.config.api}/receive`, {
+        return this.axios.get(`${this.config.api}/receive`, {
           headers,
         });
       })
@@ -119,7 +119,7 @@ export class Adapter {
     return this.getAuthorizationHeader()
       .then((headers) => {
         return this.axios.post(
-          `{this.config.api}/send`,
+          `${this.config.api}/send`,
           {
             topic,
             body,
@@ -149,7 +149,7 @@ export class Adapter {
     return this.getAuthorizationHeader()
       .then((headers) => {
         return this.axios.post(
-          `{this.config.api}/notify`,
+          `${this.config.api}/notify`,
           {
             body,
           },