Ms Team does not support cs file when the cs file is not put at first (iOS)

I use Ms team for scoring student assignment in my iPad.
I can view cs file when it is put at first. If it is at second, there is an error message ‘team cannot open file due to in supported file type’. 

I tried to update Teams and use the browser versions. The browser versions does not support too. 

please let me know how can I fix it?