I recommend that you phone contact your regional D-Link support office and ask for help and information regarding this. 
Link> Tech Support Contact Information
We find that online chat or phone contact has better immediate results over using email.
I presume warranty is still good with D-link. Ask about this.
HAHAHAHA
What a joke.  The chat support suggested that I needed to connect to the 2.4GHz band to make the connection better.  Which defeats the entire purpose of this router.
DLink has a 1 star rating from me at this point.