I have upgraded perfectly working Magento 2.2.6 to 2.3.0 last week and since then about once per day I find my store front-end down, displaying Ooops, our bad message. It keeps showing that message on page refresh. The admin pages work fine though. I fix it by Flushing Page cache and then it works fine until next occasion.
This is the only thing I found in system log reporting any kind of failure, but since I do not know at what time the store went down I cannot be sure it is related.
[2018-12-06 09:56:59] main.WARNING: No such entity with addressId =
#0 /var/www/html/store/vendor/magento/module-customer/Model/AddressRegistry.php(49): Magento\Framework\Exception\NoSuchEntityException::singleField('addressId', NULL)
#1 /var/www/html/store/vendor/magento/module-customer/Model/ResourceModel/AddressRepository.php(172): Magento\Customer\Model\AddressRegistry->retrieve(NULL)
#2 /var/www/html/store/vendor/vertex/module-tax/Model/AddressDeterminer.php(88): Magento\Customer\Model\ResourceModel\AddressRepository->getById(NULL)
#3 /var/www/html/store/vendor/vertex/module-tax/Model/AddressDeterminer.php(73): Vertex\Tax\Model\AddressDeterminer->getDefaultBilling(367)
I cannot reproduce it at will. I have no additional modules enabled other than Magepal SMTP.
What would the error above suggest though?
Thanks