Trouble w/ Online Activation, GA309 : Oops, we hit a snag. Come back later

Hi,

I recently purchased a prepaid ATT SIM card w/ 1-yr plan for unlimited talk/text and 8gb internet / mon.  When I tried the online activation at the portal, it shows the error message, " GA309 : Oops, we hit a snag. Come back later".  Can anybody help me if purchased this promotional plan and successfully activated your SIM card?  By the way, I am porting in from Sprint.