Magento 2 translate json issue - /Magento_Theme/layout/default.xml' is not valid.

Only Magento Certified developer Situation - Magento 2.2.6 Error - when trying to creat theme [login to view URL] site went down Error details: [2018-10-24 06:22:06] [login to view URL]: Theme layout update file '/home/....../public_html/app/design/frontend/Infortis/base/Magento_Theme/layout/[login to view URL]' is not valid. {"exception":"[object] (Magento\\Framework\\Config\\Dom\\ValidationException(code: 0): Theme layout update file '/home/........./public_html/app/design/frontend/Infortis/base/Magento_Theme/layout/[login to view URL]' is not valid. at /home/...../public_html/vendor/magento/framework/View/Model/Layout/[login to view URL])"} [] We use nl_NL language See also error [login to view URL] What we tried - clear everything rm -rf var/di var/generation rm -rf generated/metadata generated/code rm -rf pub/static rm -rf var/cache/ rm -rf var/composer_home rm -rf var/generation/ rm -rf var/page_cache/ rm -rf var/view_preprocessed/ - force deploy content including nl_NL, en_GB, nl_BE Still no result. See also included errorlog Result wished: - Get our Magento 2.2.6 backend live - Get our Magento 2.2.6 frontend stores live - Set default Language to nl_NL Only ftp access after reward of project.