computer is no longer authorized to play purchased items on your iPhone

You might try deauthorizing the computer, then authorize it again. Also be sure there isn't some purchased media on your phone that was purchased under a different ID (that your computer isn't authorized for).

Transfer it to your iTunes library (connect your phone to your computer, open iTunes, go to File>Devices>Transfer Purchases). Then right-click on the app in your apps folder, select Get Info, on the Summary tab look at the Apple ID field.

If it won't transfer to your iTunes library this usually indicates your computer is not authorized for the ID that was used to purchase it.

Strange. Have you tried something as simple as restarting your Mac?

You could try the troubleshooting steps listed here to see if any of them help: http://support.apple.com/kb/TS1389. You may need to try removing the SC Info folder.

Sorry, don't know what else to suggest. Unless someone else here has an idea, you may need to make an appointment with the Genius bar at a nearby Apple store to see if they have a suggestion.

You're welcome. Good luck!

Hey there,

You discussion came up in a search for the same error message that milepost included in the start of this thread.

I have the same error message across multiple devices that my family uses. It is intermittent and once I put my password in for the account it comes up with a window that says something to the effect that all 5 of 5 computers have been authorized for this account - but it seems to carry on after that.

I just wanted to add that I am seeing a similar message and do not recall anything that has changed to cause it. We are a multi iOS family but so I just wanted to confirm that the limit of 5 refers to computers - not to the number of iOS devices that may be managed on the computers - is that correct?

Correct. A maximum of 5 computers can be authorized to play or sync purchased content (see http://support.apple.com/kb/ht1420). There is no limit to the number of iOS devices can sync purchased content from an authorized computer. However, an iOS device can only sync with a single computer at a time. If you sync an iOS device with a computer and then attempt to sync the same device with a different computer, iTunes will delete all iTunes media from the device and replace it with the iTunes media from the new iTunes library it is being synced with.

Thanks for the confirmation and the link.

I will work through that as far as I can. Just as the info page warns against, I think some of my very old Macs may have gone to recycling some time ago - before I thought to deauthorize them.

I suppose I am going to have to do take the "deauthorize all" route but it leaves me a bit anxious that I will loose connections to "iTunes match" and other services that are linked to my account.

Thanks for your help.

All you will need to do after deauthorizing all is to reauthorize the ID you are using for iTunes Match (along with any other IDs used for purchased media in your library) in Store>Authorize This Computer. Then turn on iTunes Match again (Store>Turn on iTunes Match), add the computer and let it rescan your library. Then you'll be back in business. You'll need to do this on each of your computers that you are using iTunes Match on.

Just a note: you can only deauthorize all computers once/year.