My last post stated exactly the error message. First, I tap on the pen icon to enable me edit the file. I make a few changes and then tap on the "save" Icon. Then I get the error:
TypeError: Failed to fetch
The error does not mean anything to me. So I just exit without saving.
There is a real useability issue with that editor, and I think it is unfortunate. I have had that experience with the two tabs I have used with DS.