I've developed a company app for Windows Phone 8, and have gone through all the recommended steps to set it up for installation. I have a Symantec code-signing certificate, and I have generated my Application Enrollment Token and my signed XAP, which I am hosting in a public folder on OneDrive. I generated the XAP using the BuildMDILXap.ps1 script, which ran without errors. I haven't bothered with a company hub app, since we're only distributing a single app.
The AET loads OK on the phone, and asks if I would like to add the workplace account. I click "add", the dialogue box disappears, and no error comes up. There is no confirmation message, however I don't know if I should expect one.
When I load up the XAP, I get the message "Can't install company app. There's a problem with this company app. Contact your company's support person for help."
The phone has been developer unlocked (which of course isn't necessary), and I've had the app side-loaded and running on it successfully before. It was uninstalled before attempting the above, however.
I'm not sure what to do from here. I've tried recompiling and re-signing the XAP and re-generating the AET, but nothing seems to work.
After fruitlessly trying to solve this problem, I found a workaround that does what I need.
It turns out that you can post apps to the public app store, but hide them from searches, essentially making them private to anyone that doesn't have the link. That solves my first problem, getting the app published in a way that my client can access without me needing to have developer licenses for each of their phones.
The downside with that solution is that you still have to wait a few days for an update to be approved, which isn't the greatest when you're still beta-testing and need to make quick changes. However, Microsoft also have a beta program for Windows Phone apps. By designating the app as Beta, submission happens automatically within 2 hours, but you have to restrict access to specific Microsoft accounts. The latter isn't a problem because the number of devices using the app is relatively small.
This removes the need for a corporate app store in my case, and saves the expense of a certificate and the fiddling around that goes with it.