When in private browsing mode, it isn't possible to email/upload Work Acknowledgements. You can tell you're in Private Mode when the color of the bar at the top of the screen is dark, instead of light-colored.
Steps to get out of Private Mode:
- Tap the two-overlapping-squares (top-right on an iPad)
- Tap 'Private' (this word will be surrounded by a white box when in Private Mode)
- Tap the center of the screen, or 'Done'