hi Rishabh,
The fact that one push in the delivery was sent , it means the problem could be with the push payload and it may not return a correct value for some recipients.
The best way to check this is to try and preview the push messages once for the sent recipient and once for the failed recipient and then compare the source of the delivery to see what is the difference.
You may also compare the payloads for the failed and sent messages to see what is different in them
Regards,
Adhiyan