Gmail error: "Can't attach empty file"

Issue a report file is not attached to the mail has been confirmed.

1. [Settings] -> [Apps]

2. Select the [Settings] button

3. Please select the [App permissions]

4. Please select the [Storage]

5. Please be modified as image settings

6. Please make sure that the file came to be attached at the time of mail creation. (Restart of the smartphone might be necessary.)