I cannot see the changes in the source code associated with a commit. In BitBucket, I select a branch and then select the link for the associated commit, as highlighted in the screenshot below.

No matter which commit I click on, in any branch, I get the following error:

It seems to be an issue in only one repository. I previously had no issues viewing these commits in BitBucket. I'm not sure when or what triggered the issue, but it is a problem for both developers using the repositories.
Any help would be much appreciated.