Prasnop,
Well, I didn't ask for ME21N, I asked for ME22N. No Matter, the problem is probably the same.
The problem is that you are ATPing based on requirements, but GATP is not recognizing any requirements, only confirmations.
Show me the top of the 'Scope of check' screen, that you cropped off in your original screenshot.
Also, give me a screen print of the ATP page in the product master of the source location for this material. I am particularly interested in the requirements class (Check mode in SCM).
Also, do you have a requirements profile created in ECC for this plant (OLME > Purchase order > Set up STO > Assign delivery type and checking rule)? If so, display this profile in SCM (IMG > APO > GATP > General Settings > Requirements profile).
Best Regards,
DB49