We have identified the issue and have been implementing a fix. We are seeing builds succeeding again as a result. We will be restarting all failed builds from the last 15 hours.
This will cause a much longer than usual wait time. We would expect the queue to be caught up in ~5-7 hours, and will update this incident to fully resolved as soon as the queue times are back to normal.
We appreciate your understanding and patience as we get the iOS build queue back down.
If your restarted build fails again, it is likely unrelated to this incident. Please investigate the error logs as you would normally, and Submit a support ticket if you are not able to resolve the issue.