I had a perfectly working smtp notify setup in previous Home Assistant version. After upgrade to 0.110.3, everything else seems to work normally, but not smtp notify. The service is not available like it used to be. I have checked configuration.yaml many times, but it is intact, smtp notify settings are identical to before-upgrade.
My installation is Home Assistant Core on virtual environment running on Raspbian/Raspberry 4.
I just tried it with a dev checkout (~0.111.x), and it seems to work ok for me. I also just looked at the code and there are several warnings or errors it would write to the log if something goes wrong. There are also a few debug messages you can enable with:
logger:
default: info
logs:
homeassistant.components.smtp: debug
Thanks, using this logging info I was able to see that it was a login problem to Gmail account I am using for smtp messages. Generating an application password for Google account and using it made smtp to work normally.
What makes me wonder is that smtp setup worked with previous HA version without any application password. Strange… But many thanks for the logging info that guided me towards solution!