Trybot always failed for me at source code checkout stage:

Failed stdout link:

https://logs.chromium.org/v/?s=chromeos%2Fbb%2Fchromiumos.tryserver%2Frelease%2F18931%2F%2B%2Frecipes%2Fsteps%2FInitialCheckout%2F0%2Fstdout

It also happens for job of other people, so it looks like it's a common issue.

It always complain that it can't find remote branch

"fatal: Couldn't find remote ref refs/heads/release-R64-10176.B-next/chromeos-experimental\n"