Default HELP: Wifi problems with aosp roms after flashing from emg4

Hey everyone,
I have got a new galaxy s3 with i9300xxemg4 preinstalled.
I rooted the galaxy s3, saved the efs partion, flashed twrp and wanted to update to a rom like teamsek cm11.
all worked without problems. but now I have the problem that no aosp rom can connect to wifi.
I get the error "association rejected"

I did not have this problems with my old galaxy s3. I get the new one through the warranty.