There are sooooo many different passwords... I run into the same problem pretty often...
most of the time with me, i am trying to log in to my sling account with my slingbox password or the other way around.
so, if you are trying to log in to the slingplayer mobile, the password you should be using is your sling account password. not your slingbox password (either of them).
I hope that helps.
I have set up a second account, now all my passwords are the same...and I still get "the email ID or password you entered is not valid. Please try again." message. I am currently logged into slingbox.com successfully so I know the password and corresponding ID is correct. Please help.
Evo 4G - Slingplayer Mobile