Trouble sending multiple notifications using APNS

I'm trying to send multiple notifications using my PHP script. But after sending about 50 or so out of the 10k users, I get a broken pipe warning. I'm not 开发者_JAVA技巧sure whether that message is sent. From various other posts, I learnt that it could be because of a invalid token. However, my feedback service returns no invalid tokens. (ssl://feedback.push.apple.com:2196) Tried this both in production mode and sandbox mode.

What other reasons could cause this invalid pipe issue?

My exact problem is explained here by someone else as well.

http://pastie.org/698787.txt

Apple's servers will drop the connection as soon as there is something wrong in the stream of your push messages.

Be careful with mixing device tokens between sandbox and production modes. There's an article here that describes the issue.

Also, have you tried using the enhanced notification format described in Apple's documentation? The response might tell you what's wrong.