HT1420 Authorized/No longer Authorized error message

Question

I have authorized my computer but whenever I sync I get an error message that says "This computer is no longer authorized for apps installed on your iphone." It then asks me to authorize or it will delete apps from my phone.  When I click "Authorize" it tells me that "this computer is already authorized."
I went into iTunes and de-authorized all computers, then re-authorized this one but still get these errors. Any ideas?

Answer 1

No. You must purchase them under your Apple ID. Anything purchased under someone else's Apple ID will present this same issue. You cannot share items in this way.
Give the above see the following:
Sharing Stuff From Different iTunes Accounts (or Computers)
Here's how to do so using different computers:
Transfer what content you want to the separate iTunes library on each computer. To transfer content from your library to another library do the following. We'll assume this is between husband and wife separate accounts and different Apple IDs.
Launch iTunes under your wife's login;
Sign her out of iTunes, then you sign in;
Select iTunes -> Preferences -> Devices -> Disable auto-sync when an iPod/iPhone is connected;
Connect your phone, DO NOT SYNC;
Select Store -> Authorize this Computer (only have to do this once);
Select File -> Transfer Purchases (all of the purchased content on your phone will be transferred to your wife's library);
When complete eject your phone, sign out of iTunes, sign your wife back in.
You can now sync whatever content you want to your wife's phone. Just remember all updates to apps obtained using your account must be done while signed in using your account: sign wife out, you sign in, update apps, you sign out, sign wife in, sync her phone.
This way you can share content (permitted under the EUSLA) and still maintain your separate logins. Do the same on your computer if you want to share content from your wife's library.
Just load whatever content you want to share on each others phones, transfer the content, then delete it from the respective phone if you don't want to keep it there.
Contributed by user wjosten and modified by me.