Error when attempting a refund

I am attempting to process a refund for a customer. I’ve had errors in the past when I’ve done refunds, but this is the first time I’m seeing this:
Could not get the results of the charge-back attempt.

It seems to be only happening with this customer because I processed another refund with a different customer and I had no problems. I have attempted to process this refund on several different days and I continue to get the same error.