Re-save all products in Magento2 - Weird error has forced me to manually resave products to get configurable options to show up on frontend. This Issue appears now and then and we have to Re-Save the products again and again.
I had the same issue: after import I has to re-save products to show, because my re-index was set to 'Update on save'. It means I had to save goods. I figured this out coming across this article. So you can check your settings and if you have the same, run re-index manually.