While adding and editing product attributes from backend in magento 2 it gives HTTP ERROR 500
If you're getting an error 500 probably you'll find a message into the Magento's logs and mayube even into your webserver error log.
Can you check those files?
I am getting following error while adding/editing product attributes from store in magento 2
PHP Parse error: syntax error, unexpected '?' in /public_html/test/vendor/magento/module-swatches/view/adminhtml/templates/catalog/product/attribute/visual.phtml on line 88
Which version of Magento are you using?
I am using 2.1.0 magento version. I am using huge theme for magento which requires this verison.