The error is a little confusing because the the "File exists:" warning, but I think (I hope) that the "No URLs matched" error is independent of that.

stout-release build 3704:

https://uberchromegw.corp.google.com/i/chromeos/builders/stout-release/builds/3704/steps/PaygenBuildCanary/logs/stdio

15:41:36: ERROR: <class 'chromite.lib.gs.GSCommandError'>: return code: 1; command: /b/cbuild/internal_master/.cache/common/gsutil_4.19.tar.gz/gsutil/gsutil -o 'Boto:num_retries=10' stat -- gs://chromeos-releases/canary-channel/stout/9350.0.0/payloads/signing/30351-140567909639936/1.payload.hash.update_signer.signed.bin
WARNING 0308 15:37:20.949559 oauth2_client.py] FileSystemTokenCache.PutToken: Failed to create cache file /tmp/cbuildbot-tmp8GRNIp/oauth2_client-tokencache.1001.534d7de05989f9d65394a17ce0e37362d9e78f83: [Errno 17] File exists: '/tmp/cbuildbot-tmp8GRNIp/oauth2_client-tokencache.1001.534d7de05989f9d65394a17ce0e37362d9e78f83'
No URLs matched: gs://chromeos-releases/canary-channel/stout/9350.0.0/payloads/signing/30351-140567909639936/1.payload.hash.update_signer.signed.bin
cmd=['/b/cbuild/internal_master/.cache/common/gsutil_4.19.tar.gz/gsutil/gsutil', '-o', 'Boto:num_retries=10', 'stat', '--', 'gs://chromeos-releases/canary-channel/stout/9350.0.0/payloads/signing/30351-140567909639936/1.payload.hash.update_signer.signed.bin'], extra env={'BOTO_CONFIG': '/b/build/site_config/.boto'}