Do a git checkout of the target repo:
git clone https://skia.googlesource.com/git-master-skia
Then point to that directory as the url handed to androidingest as the --repo_url. This will give you up to date commits, but also doesn't require write access to the origin repo. You will probably have to be on a non-master branch in the checkout so that the copy androidingest builds can push back to it.
The process of creating git commits to mirror buildids has too high on an error rate.
Check the logs for the exact operation in the process that is failing.
The storing of all uploaded data in the transaction log is failing. Check GCS permissions and the logs for the errors generated.