I am having an issue with Magento 2.2.0
All order templates are being received blank with no content even though in the email templates it is there....
Please check in Sales configuration all email templates are set properly or not? or save it again from admin
or try this too
May be you did migrarion from m1 to m2 and setting exist into core_config_data.
So go to sales email setting set default value and check it
Can you check log file ?
do one thing remove all log and send email from order email and check log