Publishers and advertisers are unhappy with the limitations on ads in iOS 9s Apple News app, according to a report in the New York Post.

Apple News brings together articles from a multitude of publishers in one app, similar to Instant Articles on Facebook – and, according to a story today, a forthcoming product from Google and Twitter.

Publishers are able to advertise on their content in Apple News, but with restrictions that are reportedly proving unpopular. Real-time bidding isnt currently available, for example, nor is buying through Googles DoubleClick platform.

The single largest bugbear, however, seems to be Apples content approval requirements. All campaigns must be approved with 48 hours’ notice, and pre-roll video ads have to be directly vetted – a process that one source described as “very difficult” to negotiate.

At least one complaint from the publishers side has already been addressed, with Apple making it possible to link back to their own websites. Whether the same will happen for advertisers remains to be seen.