MC-21568: The shipping information was unable to be saved. verify the input data and try again.

Author: rostyslav-hymon

app/code/Magento/Persistent/Model/QuoteManager.php

@@ -89,7 +89,6 @@ public function setGuest($checkQuote = false)
                 ->setCustomerLastname(null)
                 ->setCustomerGroupId(\Magento\Customer\Api\Data\GroupInterface::NOT_LOGGED_IN_ID)
                 ->setIsPersistent(false)
-                ->setCustomerIsGuest(true)
                 ->removeAllAddresses();
             //Create guest addresses
             $quote->getShippingAddress();