Error 927 while updating YouTube
Method 1 :

Go to Settings -&gt; Applications and find Google Play. Then > Clear Cache.

or

Method 2 :

Go to Settings &gt; Accounts &gt; Google and remove your google account. Then add it back to the device and try redownload or reupdate the App. If it doesn't work and the error is still there give it some time. It'll likely clear itself out and you'll be able to download the App later.

Sources and other Links :

Error 927 Google Play (Xda forum)

Error 927 Google playstore (androidcentral)

Android Fix: Error 927 while downloading or updating apps in Google Play Store

Different Ways To Get Rid Of Error 927 In Android