diff --git a/pom.xml b/pom.xml
index c4d3d43ba5b19bd9d7ff9a0f302981748a536df6..84ecdd76ec530aa5cd1d172983569f3a6da79a72 100644
--- a/pom.xml
+++ b/pom.xml
@@ -91,7 +91,7 @@
 		<dependency>
 			<groupId>com.github.scribejava</groupId>
 			<artifactId>scribejava-core</artifactId>
-			<version>4.2.0</version>
+			<version>6.2.0</version>
 		</dependency>
         <dependency>
             <groupId>org.slf4j</groupId>
diff --git a/src/main/java/org/genesys2/client/oauth/GenesysClient.java b/src/main/java/org/genesys2/client/oauth/GenesysClient.java
index d45fd2be79e455101f663b872aaa83e7d89d77c5..77c98679a62af5367d6756d8417308bff007d21b 100644
--- a/src/main/java/org/genesys2/client/oauth/GenesysClient.java
+++ b/src/main/java/org/genesys2/client/oauth/GenesysClient.java
@@ -42,6 +42,7 @@ import com.fasterxml.jackson.databind.SerializationFeature;
 import com.fasterxml.jackson.databind.node.ArrayNode;
 import com.fasterxml.jackson.databind.node.ObjectNode;
 import com.github.scribejava.core.builder.ServiceBuilder;
+import com.github.scribejava.core.exceptions.OAuthException;
 import com.github.scribejava.core.model.OAuth2AccessToken;
 import com.github.scribejava.core.model.OAuthRequest;
 import com.github.scribejava.core.model.Response;
@@ -581,6 +582,29 @@ public class GenesysClient {
 		}
 	}
 
+	/**
+	 * Obtain access and refresh tokens with client id and secret.
+	 *
+	 * @throws OAuthAuthenticationException
+	 */
+	public void authenticate() throws OAuthAuthenticationException {
+		try {
+			OAuth2AccessToken accessToken = service.getAccessTokenClientCredentialsGrant();
+
+			LOG.info("ACCESS TOKEN: {} scope={} raw={}", accessToken.getAccessToken(), accessToken.getScope(), accessToken.getRawResponse());
+
+			final String refreshToken = accessToken.getRefreshToken();
+			LOG.info("REFRESH TOKEN: {}", refreshToken);
+
+			tokens.setAccessToken(accessToken.getAccessToken());
+			tokens.setRefreshToken(refreshToken);
+
+		} catch (OAuthException | IOException | InterruptedException | ExecutionException e) {
+			LOG.error("Auth error", e);
+			throw new OAuthAuthenticationException(e.getMessage());
+		}
+	}
+
 	/**
 	 * Obtain access and refresh tokens with verifier code.
 	 *
diff --git a/src/main/java/org/genesys2/client/oauth/api/GenesysApi.java b/src/main/java/org/genesys2/client/oauth/api/GenesysApi.java
index 1188ac2e6c435bd7ce9e177a5c569447649e2a8d..d8ab54b89151ad773311119cdbd120d3474bfcb4 100644
--- a/src/main/java/org/genesys2/client/oauth/api/GenesysApi.java
+++ b/src/main/java/org/genesys2/client/oauth/api/GenesysApi.java
@@ -17,7 +17,6 @@
 package org.genesys2.client.oauth.api;
 
 import com.github.scribejava.core.builder.api.DefaultApi20;
-import com.github.scribejava.core.builder.api.OAuth2SignatureType;
 
 /**
  * Genesys API v1.
@@ -52,11 +51,6 @@ public class GenesysApi extends DefaultApi20 {
 		return baseUrl + AUTHORIZE_ENDPOINT;
 	}
 
-	@Override
-	public OAuth2SignatureType getSignatureType() {
-		return OAuth2SignatureType.BEARER_AUTHORIZATION_REQUEST_HEADER_FIELD;
-	}
-
 	/**
 	 * Gets the base url.
 	 *