Since the 5.0.2 update to my Sprint One M7, the Play Store has been all kinds of messed up.
Typically, it will fail to load and display the DF-DFER-01 error code, although it also sometimes displays a generic Network Timeout message.
I have cleared cache/data for Play Store, Play Services, and Google Services Framework. I've uninstalled updates to all the above. I've tried sideloading various versions of the Play Store app. I've removed and re-added my Google accounts. I've even done three hard resets (from the fastboot menu), and every time, I sign back in to my google account and the Play Store app comes right back with "error retrieving data from server."
If a hard reset doesn't fix it I'm not sure what to do...my guess is some of the Android system files that aren't affected by a factory reset have become corrupted. Any ideas would be appreciated...