diff --git a/src/API/Auth/Basic.php b/src/API/Auth/Basic.php
index f9ccf84..6cb874b 100644
--- a/src/API/Auth/Basic.php
+++ b/src/API/Auth/Basic.php
@@ -12,6 +12,10 @@ public function auth() {
 		return true;
 	}
 
+	public function get_url() {
+		return '';
+	}
+
 	abstract protected function get_username();
 
 	abstract protected function get_password();
diff --git a/src/API/Auth/OAuth.php b/src/API/Auth/OAuth.php
index 738660a..fa0fa02 100644
--- a/src/API/Auth/OAuth.php
+++ b/src/API/Auth/OAuth.php
@@ -10,6 +10,8 @@ public function get_type() {
 
 	abstract protected function get_access_token();
 
+	abstract public function get_url();
+
 	public function get_headers() {
 		$headers = array();
 
diff --git a/src/API/REST.php b/src/API/REST.php
index 06e4cff..5b22cff 100644
--- a/src/API/REST.php
+++ b/src/API/REST.php
@@ -34,7 +34,13 @@ protected function get_auth() {
 	 * @return bool
 	 */
 	protected function is_auth_request( $url ) {
-		return strstr( $url, $this->get_auth()->get_url() );
+		$auth_url = $this->get_auth()->get_url();
+
+		if ( empty( $auth_url ) ) {
+			return false;
+		}
+
+		return strstr( $url, $auth_url );
 	}
 
 	protected function get_timeout( $request_type = 'GET' ) {
@@ -68,7 +74,6 @@ protected function maybe_encode_body( $body_args, $content_type = '' ) {
 	 * @return Response
 	 */
 	protected function get_response( $url, $type = 'GET', $body_args = array(), $headers = array() ) {
-		$headers         = $this->get_headers( $headers );
 		$response        = false;
 		$is_auth_request = false;
 
@@ -78,6 +83,12 @@ protected function get_response( $url, $type = 'GET', $body_args = array(), $hea
 			$auth_response = $this->get_auth()->auth();
 		}
 
+		/**
+		 * Need to build-up headers after (potentially) performing the auth request
+		 * to make sure new auth headers are set.
+		 */
+		$headers = $this->get_headers( $headers );
+
 		if ( 'GET' === $type ) {
 			$response = wp_remote_get(
 				esc_url_raw( $url ),
diff --git a/src/DataStores/Shipment.php b/src/DataStores/Shipment.php
index bbf5aed..dc2f68c 100644
--- a/src/DataStores/Shipment.php
+++ b/src/DataStores/Shipment.php
@@ -206,7 +206,6 @@ public function update( &$shipment ) {
 
 		// Shipping provider has changed - lets remove existing label
 		if ( in_array( 'shipping_provider', $changed_props, true ) ) {
-
 			if ( $shipment->supports_label() && $shipment->has_label() ) {
 				$shipment->get_label()->delete();
 			}
diff --git a/src/Install.php b/src/Install.php
index 743c5ee..f49eac8 100644
--- a/src/Install.php
+++ b/src/Install.php
@@ -549,7 +549,7 @@ private static function get_schema() {
   shipment_date_sent_gmt datetime default NULL,
   shipment_est_delivery_date datetime default NULL,
   shipment_est_delivery_date_gmt datetime default NULL,
-  shipment_status varchar(20) NOT NULL default 'gzd-draft',
+  shipment_status varchar(150) NOT NULL default 'gzd-draft',
   shipment_order_id bigint(20) unsigned NOT NULL DEFAULT 0,
   shipment_packaging_id bigint(20) unsigned NOT NULL DEFAULT 0,
   shipment_parent_id bigint(20) unsigned NOT NULL DEFAULT 0,
diff --git a/src/PickupDelivery.php b/src/PickupDelivery.php
index a1596d2..cc4f8fb 100644
--- a/src/PickupDelivery.php
+++ b/src/PickupDelivery.php
@@ -716,14 +716,20 @@ public static function register_assets() {
 	}
 
 	public static function get_excluded_gateways() {
+		$excluded_gateways = array( 'cod' );
+
+		if ( ! is_admin() ) {
+			$excluded_gateways[] = 'amazon_payments_advanced';
+		}
+
 		/**
 		 * Filter to disable pickup delivery for certain gateways.
 		 *
 		 * @param array $gateways Array of gateway IDs to exclude.
 		 */
-		$codes = apply_filters( 'woocommerce_gzd_shipments_pickup_delivery_excluded_gateways', array( 'cod', 'amazon_payments_advanced' ) );
+		$excluded_gateways = apply_filters( 'woocommerce_gzd_shipments_pickup_delivery_excluded_gateways', $excluded_gateways );
 
-		return $codes;
+		return $excluded_gateways;
 	}
 
 	public static function get_pickup_delivery_cart_args() {