Tests have been nearly all red since 10 AM on June 11.

What version of gRPC and what language are you using?

Head, PRs, Python

What operating system (Linux, Windows,...) and version?

MacOS

What runtime / compiler are you using (e.g. python version or version of gcc)

CI platform

What did you do?

Tried to create a PR

What did you expect to see?

Green test

What did you see instead?

Red tests for several hours according to https://fusion.corp.google.com/projectanalysis/summary/KOKORO/prod%3Agrpc%2Fcore%2Fpull_request%2Fmacos%2Fgrpc_basictests_python

Anything else we should know about your project / environment?