diff --git a/src/net/nodefetchclient.ts b/src/net/nodefetchclient.ts
index d2189fd1..d8531f3b 100644
--- a/src/net/nodefetchclient.ts
+++ b/src/net/nodefetchclient.ts
@@ -64,7 +64,7 @@ export class NodeFetchClient implements HttpClientImpl {
                 let body = [];
                 body.push("grant_type=client_credentials");
                 body.push(`client_id=${formattedClientId}`);
-                body.push(`client_secret=${this._clientSecret}`);
+                body.push(`client_secret=${encodeURIComponent(this._clientSecret)}`);
                 body.push(`resource=${resource}`);
 
                 return nodeFetch(authUrl, {