This could be an issue with ur internet connection so check that first by downloading speedtest.net (its an app) from the playstore and running it.
Secondly charge up ur phone. Sometimes the updates don't run on low battery because samsung thinks that the battery might die in the middle of the update and the phone will get bricked (stuck with only half the software)
Do both those things and retry. If it doesn't still work, comment here.
If my comment helped you in any way, please consider hitting the 3 dot menu and accepting my answer as a solution.
