Magento version 2.1.1
Configuable product with click on swatches 'updateData' of undefined error comes in swatches-render.js file at line no. 920
updateBaseImage @ swatch-renderer.js:920
(anonymous function) @ jquery-ui.js:402
_ProductMediaCallback @ swatch-renderer.js:849
(anonymous function) @ jquery-ui.js:402
mediaSuccessCallback @ swatch-renderer.js:740
fire @ jquery.js:3099
fireWith @ jquery.js:3211
done @ jquery.js:9310
callback @ jquery.js:9720
Above error log are generate on console when click of any config product swatches.
Based on Above error Product are not added to cart and display message when add to cart from details page,
You need to choose options for your item. Error are generate and product not added to cart.
