I had the same problem as yours.do n know why, but this 's what I tried >click setting >wifi >click the arrrow(>)on my home network >click forget this network >restart my iphone > reconect to my network . Hope it 'll help.
Kudos to Fearless. It worked exactly as he said it!
EDIT: Sadly, the same problem reappeared after few days. The fix wasn't permanent