Error 9006 on updating iPhone

I am attempting to update my iPhone but there is a gray error box that will appear with a message, "There was a problem downloading the software for the iPhone. An unknown error occurred (9006). Make sure your network settings are correct and your network connection is active or try again later." I tried again after some time but it's still the same. Is this an issue with my connection? Please send me some ideas on how to fix it. Thank you.

