Error code sg3126 in Internet mode ?

[Zouave]

when i try to connect to internet mode. i can't get through and the game return
error code sg3126. What's this code mean? And how to fix it?

I think my wireless and internet connection is ok because i can enter psn store.

[Illuminate]

You need an internet multimode code to play PSP2 demo online.

[Zouave]

i've already have the code and enter it few days ago.
but i still can't get through because error sg3126. So bad T^T