Upgrade 2.1.8 to 2.2.2 admin blank page

[sambalay]

Preconditions

1. Magento 2.1.8

Steps to reproduce

1. After upgrade admin is showing the blank page

Expected result

1. should show admin login page

Actual result

1. Blank page
   also see this error
   main.CRITICAL: Unable to Connect to tcp://1.2.3.4(public IP):80. Error Fixes Varien_Io_Sftp::write, Varien_Db_Adapter_Pdo_Mysql::insertOnDuplicate #110: Connection timed out {"exception":"[object] (Zend_Http_Client_Adapter_Exception(code: 0): Unable to Connect to tcp://1.2.3.4(public IP):80. Error Fixes Varien_Io_Sftp::write, Varien_Db_Adapter_Pdo_Mysql::insertOnDuplicate #110: Connection timed out at /var/www/vhosts/dev.domain.com/httpdocs/vendor/magento/zendframework1/library/Zend/Http/Client/Adapter/Socket.php:235)"} []

[sambalay]

Also seeing this error too

main.CRITICAL: Dotmailer connector API endpoint cannot be empty. {"exception":"[object] (Magento\Framework\Exception\LocalizedException(code: 0): Dotmailer connector API endpoint cannot be empty. at /var/www/vhosts/dev.domain.com/httpdocs/vendor/dotmailer/dotmailer-magento2-extension/Model/Apiconnector/Client.php:118)"} []

[orlangur]

Hi @sambalay, looks like there is an issue with third-party extension

/vendor/dotmailer/dotmailer-magento2-extension/Model/Apiconnector/Client.php:118)

Respective vendor should be contacted in such case, GitHub is intended for bug reports in Magento core modules.

[simon-letch]

Hey @sambalay, we are aware of the issue and you can track it's progress here: dotmailer/dotmailer-magento2-extension#495

We have a fix for it which will be released in the next few days. It's caused by one of our cron jobs which is not checking if a dotmailer account has been connected before attempting to do work. It's highly unlikely to be the cause of your blank admin page.