Do one of the following:
- Make sure that the device ID (UDID) is included in the mobileprovision file. After you add the UDID, select it before updating the mobile provisioning file. Also double-check that you are using the most recent version of your mobile provision file.
- Make sure that the .p12 certificate is valid. Check to see if the certificate requires updating.
For more information on creating the relevant files and certificates for your iOS app, see iOS Publishing Guide.