This message refers to the c101a7d1, 80004005 and license-reset on reinstall Store issue which has affected Phototag and many other apps.
Due to a Store-related bug beyond my control, a subset of users who had installed Phototag BEFORE the February 2015 update may have had their license for the app incorrectly invalidated by the system. As a result of this bug, the app could not be updated. Even after uninstalling the app, the app failed to reinstall. Although the app may be reinstalled via the Windows Phone website, users who had originally owned the paid version saw the app reverted to trial. Again, I'd like to remind users that this is not a bug that developers can fix. Rather, the issue stems from Microsoft's end and it is only Microsoft who is in the position to potentially fix the bug.
For those who had paid money for the app and lost your license, please contact your region-specific Windows Phone Support to help assist you in reinstalling the app and reinstate your licence using the add-credit/repurchase workaround with no additional cost to you.
If you had "purchased" the app via a free promo, you may also try contacting Windows Phone Support and request for the workaround as mentioned above. Do note however that not all of the Microsoft staff in the various regions are on the same page on how to resolve such a case. Some of them are putting the fault at the app or developer; this is of course not true as Microsoft had already admitted to the Store bug back in April 2015. Anyway, I need feedback on this so that I can pass it a long to my point-of-contact at Microsoft.
Note that as some users had pointed out, a factory reset (or hard reset) of the phone does not automatically resolve the issue. If Windows Phone Support advises you to do that, if possible, please request for the above workaround instead.
To contact Windows Phone Support:
1. Go to windowsphone.com for your region
2. Go to the page footer and click Contact (in your language)
3. Click "Windows Phone Support" (in your language)
4. Choose Apps+Store > Contact Us > Chat Support (in your language)
Please feel free to reach out to me should you need further clarification or if you'd like to share your experience about your dealings with Windows Phone Support. I apologize for the inconvenience and thanks for your understanding and support.
P.S. It would be highly appreciated that those of you who had left a low rating because of the issue to reconsider your rating to better reflect the quality of the app rather than the Store (which I have no control of). Thanks! :)