Unable to process app at this time due to a general error

This is probably an Apple server issue, not an Xcode/iOS/OSX issue. Just wait patiently and Apple's servers will catch up to the traffic, or solve whatever issues they're having at their end.

If you're anxious, feel free to just sit there and restart Xcode until it works - but it's not restarting Xcode, only the time you waste that's solving the issue.

I had the same problem and waited for hours.

I figured out that my provisioning profile was not configured correctly.

My approach:

1. Delete distribution provisioning profile in dev center.
2. Create a new one (I used the wildcard app ID)
3. Update your profiles in Xcode settings
4. Choose the new profile when submitting the app