Itunes Connect can't submit due to language error

Solution: I had the same problem. With the new update, there is a Media Manager beneath the screen shots. Even though it is giving you a Language error, the problem is with the screen shots. Simply open the media manager and make sure that every size either has its own image or you can click the checkbox to use the two required sizes. That fixed my Language error issue.

I met the similiar situation yesterday, I thought that's result from the iTunes connect update August 8 2016, red exclamation by all localized language without others information. If you meet this situation from August 8 2016, maybe it's the case.

I contacted Apple support and finally submitted new version since I filled up screen-shots for all sizes.

while you can upload the maximum size screenshot and 're-use' it for smaller size at 'Media Manager' page.