Help WiFi Authentication Error

My tablet just randomly disconnects from the wifi with a Authentication Error....why? Its works fine when connected I'll be watching YouTube and BAM its gone like(Da Hell Happend)
Any idea what it is

Its called a RCA Voyager II(2)....I think


Check six!
This points to a problem with either the password or the encryption settings. The real question is, why does it disconnct at all once connected?

Is this a recent development i.e. was the wifi connection stable previously? If so did anything change around the same time, such as a router firmware update or software update for the tablet?