diff --git a/src/__tests__/paxfulapi_refresh_test.ts b/src/__tests__/paxfulapi_refresh_test.ts
index a529418..d8eb708 100644
--- a/src/__tests__/paxfulapi_refresh_test.ts
+++ b/src/__tests__/paxfulapi_refresh_test.ts
@@ -30,9 +30,14 @@ describe("With the Paxful API SDK", function () {
     const GET_PROFILE_URL = "/oauth2/userinfo/";
 
     it("Client credentials reset flow. Get profile", async () => {
+        const initialAccessToken = UUID();
+
         fetchMock.once({
             url: /oauth2\/userinfo/,
-            method: "GET"
+            method: "GET",
+            headers: {
+                Authorization: 'Bearer ' + initialAccessToken
+            }
         }, {
             status: 401,
             body: ""
@@ -56,15 +61,19 @@ describe("With the Paxful API SDK", function () {
         fetchMock.once({
             name: 'correct_access_token',
             url: /oauth2\/userinfo/,
-            method: "GET"
+            method: "GET",
+            headers: {
+                Authorization: 'Bearer abc'
+            }
         }, {
             status: 200,
             body: JSON.stringify({ some: "lala" })
         });
 
+
         credentialStorage.getCredentials.mockReturnValue({
             ...{
-                accessToken: UUID(),
+                accessToken: initialAccessToken,
                 refreshToken: UUID(),
             },
             expiresAt: new Date()
diff --git a/src/commands/RefreshIfNeeded.ts b/src/commands/RefreshIfNeeded.ts
index 3f190b9..dfc9dd2 100644
--- a/src/commands/RefreshIfNeeded.ts
+++ b/src/commands/RefreshIfNeeded.ts
@@ -59,7 +59,7 @@ const createRefreshRequest = async (request: Request, config: ApiConfiguration,
 
     credentialStorage.saveCredentials(credentials);
 
-    request.headers["Authorization"] = `Bearer ${credentials.accessToken}`;
+    request.headers.set("Authorization", `Bearer ${credentials.accessToken}`)
 
     return Promise.resolve(request);
 }