I archived and submitted a cordova app using Xcode. On testing locally, I find that the icon is correctly shown on the app itself, but when I go to iTunes Connect, the app i
Update September 2020. AppStoreConnect has now updated the app settings homepage and removed the upload App Icon option, now it will automatically pick the App Icon from binary.
When you have a new app, and you upload it to the appstore the icon will remain "blank" - even if it verified correctly after the upload, your bundle contains the icon, and your app displays it correctly in the dock.
Only after you click "Submit for Review" the first time, it will appear ( not entirely sure if it's instant, but I know for a fact it was there when I checked 1-2 hours after submitting it for review ).
You should upload App Icon at iTunesConnect. Provide it in 1024x1024
https://developer.apple.com/library/ios/documentation/LanguagesUtilities/Conceptual/iTunesConnect_Guide/Chapters/FirstSteps.html#//apple_ref/doc/uid/TP40011225-CH19-SW9
In my case, the app icon for Mac OS (1024x1024) did not appear when I published the Mac version of my iPad app (with Mac Catalyst)
These are the steps to follow:
Step 1: select Images.xcassets folder
Step 2: select AppIcon group and mark the unmarked checkbox "Mac" (Remember: is an iPad app for iOS that now can be available for Mac OS)
Step 3: add icons for Mac. Then, when you send for review the app for Mac (iOS app) the app icon appear on your iTunes Connect record and the error message: "App icon 1024x1024 missing", will disappear.