Magento 2 GraphQL – Cart Query Getting Error

In GraphQL when I running below queries getting error.

Mutation :

mutation customerAccessTokenCreate {
  generateCustomerToken(
    email: "test@test.com",
    password: "Test@123"
  ) {
    token
  }
}


{
  customerCart {
    id
    items {
      id
      product {
        name
        sku
      }
      quantity
    }
  }
}

Query :

{
    cart(cart_id: "dmCaKmh6zzm4KDSMSOGGkS75sB071857") {
    email
        shipping_addresses {
          available_shipping_methods {
            amount {
              currency
              value
            }
          }
        }   
    }
}

Error :

{
    "messages": {
        "error": [
            {
                "code": 500,
                "message": "Fatal Error: 'Allowed memory size of 792723456 bytes exhausted (tried to allocate 67108872 bytes)' in '/var/www/html/m2/vendor/magento/zendframework1/library/Zend/Db/Select.php' on line 1004",
                "trace": "Trace is not available."
            }
        ]
    }
}