Roku streambar problem red light flashing on the front

I just bought the Roku streambar se and when I connect it to my wifi it says wifi connected then it says looking for software up then says downloading it spins for a little bit then my TV screen saver turns on and says no single and a red light is flashing I looked up what that means and I don't understand I have it plugged straight into the wall outlet so I took that one back to the store and got a new one and it does the same thing I don't know what to do.