I have a site running with Magento 2.2.1, after upgrading to 2.3.3 with this guide, running bin/magento setup:upgrade returns error: The attribute can't be deleted.
I modified core file to get the stack trace and here is it:
#0 /var/www/html/sitedir/vendor/magento/framework/Model/ResourceModel/Db/AbstractDb.php(448): Magento\Eav\Model\ResourceModel\Entity\Attribute->_beforeDelete(Object(Magento\Customer\Model\Attribute))
#1 /var/www/html/sitedir/generated/code/Magento/Eav/Model/ResourceModel/Entity/Attribute/Interceptor.php(245): Magento\Framework\Model\ResourceModel\Db\AbstractDb->delete(Object(Magento\Customer\Model\Attribute))
#2 /var/www/html/sitedir/vendor/magento/module-eav/Model/AttributeRepository.php(183): Magento\Eav\Model\ResourceModel\Entity\Attribute\Interceptor->delete(Object(Magento\Customer\Model\Attribute))
#3 /var/www/html/sitedir/vendor/vertex/module-tax/Setup/UpgradeData.php(77): Magento\Eav\Model\AttributeRepository->delete(Object(Magento\Customer\Model\Attribute))
#4 /var/www/html/sitedir/vendor/vertex/module-tax/Setup/UpgradeData.php(58): Vertex\Tax\Setup\UpgradeData->deleteCustomAttribute()
#5 /var/www/html/sitedir/setup/src/Magento/Setup/Model/Installer.php(988): Vertex\Tax\Setup\UpgradeData->upgrade(Object(Magento\Setup\Module\DataSetup), Object(Magento\Setup\Model\ModuleContext))
#6 /var/www/html/sitedir/setup/src/Magento/Setup/Model/Installer.php(875): Magento\Setup\Model\Installer->handleDBSchemaData(Object(Magento\Setup\Module\DataSetup), 'data', Array)
#7 /var/www/html/sitedir/setup/src/Magento/Setup/Console/Command/UpgradeCommand.php(123): Magento\Setup\Model\Installer->installDataFixtures(Array)
#8 /var/www/html/sitedir/vendor/symfony/console/Command/Command.php(255): Magento\Setup\Console\Command\UpgradeCommand->execute(Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))
#9 /var/www/html/sitedir/vendor/symfony/console/Application.php(893): Symfony\Component\Console\Command\Command->run(Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))
#10 /var/www/html/sitedir/vendor/symfony/console/Application.php(262): Symfony\Component\Console\Application->doRunCommand(Object(Magento\Setup\Console\Command\UpgradeCommand), Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))
#11 /var/www/html/sitedir/vendor/magento/framework/Console/Cli.php(105): Symfony\Component\Console\Application->doRun(Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))
#12 /var/www/html/sitedir/vendor/symfony/console/Application.php(145): Magento\Framework\Console\Cli->doRun(Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))
#13 /var/www/html/sitedir/bin/magento(23): Symfony\Component\Console\Application->run()
#14 {main}
How to fix this problems?
