I was facing this problem and got error DF-DLA-15 notification when i updating apps in Play Store. I had Chinese Based ROM (MIUI 8 cn) and installed GApps from Google Installer. It perfectly installed GApps. I tried to login to google account and succeed, been trying to open Play Store, it opened smoothly.
But the problem occurred when i was trying to update apps. The DF-DLA-15 error code showed up. The workarounds is relatively simple.
Step to fix DF-DLA-15 error code:
1. Go to Settings -> Apps / Installed Apps -> Select Google Play Services
2. Clear Cache and Clear Data
3. Do the same with Google Play Store
If it doesn't work, do this step:
Go to Accounts and delete your play store account and add it back again.
It solved my problem with my Redmi Note 3 Device using MIUI 8 Developen Cn ROM.