itms-services link intermitently "cannot connect to server"

I'm currently developing an enterprise distribution platform for iOS apps. Im storing my files on AWS S3 and generating a signed URL to the plist and ipa. Everything works except intermitently i get an error of "cannot connect to bucketname.s3-eu-west-1.amazonaws.com". This error occurs about 1 in four times.

I'm using boto to generate the signed urls and when i test the urls in the browser that are used when i get the error they work perfectly fine.

Could this be an AWS issue?

Any ideas are appreciated.