My setup was working fine, but stopped working a couple of weeks ago. All devices were showing “offline” in the Google Home app. Curiously, they would work fine from the pop-up that was displayed after a “sync my devices” command – just the regular list of devices was an issue.
After trying our with CloudFlare configs, I found out one of the ranges from this post had to be updated (66.249.80.0/29 to 66.249.80.0/20, based on Expose Home Assistant For Google IPs only- IPV4 only).
My new (working) list is:
108.177.0.0/17
192.178.0.0/15
66.102.0.0/20
74.125.0.0/16
66.249.80.0/20