I'm having the same problem. The issue just started yesterday. We submit app updates almost daily. The button just stoped working. The pointer changes as normal but then nothing happens when clicked.

There seems to be a major issue with Apple's Screenshot Processing! This started Sep. 1st where some screenshots will get processed and others will just fail apparently. Fastlane deployments are just hanging for HOURS: Waiting for all the screenshots to finish being processed..." I left a deployment running for ~4 hour with no response from the API. Manually uploading via the Web portal is seriously hosed as-well! My observations: Once you upload screenshots all indications show everything uploaded and is ready to go... WRONG! If you try to submit you'll get: "There are screenshot uploads in progress" If you refresh the web page you will find a grey-cloud placeholder image. This is the screenshot that failed or didn't finish processing before the page was refreshed. The only workaround I have found: Upload one set of screenshots, DO NOT change tabs or view. Wait about 5-10 minutes then refresh the page and see if all screenshots finished processing. If not, delete the failed placeholders screenshot and repeat until all have finished processing.