When you open a shell inside the container and run env | grep "GF_" do you see all your values?
I have mine configured exactly like yours and it works just fine. There should be errors in /srv/logs/grafana.log if the SMTP server is rejecting the email. the screenshot feels like a generic error from grafana vs not actually setup. With gmail I had to make sure that the from address and user matched or gmail would silently blackhole the message so as not to give away info on what emails do/don’t exist…maybe your SMTP server does the same?
You can do an SMTP test via telnet pretty easy to make sure the server will accpt mail from your host…worked at many orgs that didn’t allow unauthenticated relaying or restricted sending IP’s so that workstations couldn’t become spam zombies. Just do a yum install telnet inside the PMM container. It looks something like:
telnet smtp.server 25
helo test
mail from: user@domain.com
rcpt to: recipient@domain.com
data
subject: test
this is a test message
(note there’s a double enter after the message to trigger the actual send)