Troubleshooting Email Notification on AWX

Hello everyone,
I’m trying to send notifications from AWX. I’ve configured parameters into Notifications in WebUI and status has Failed.
Ok, there’re some issues but I don’t know how to troubleshooting this.
I took a look into both containers awx-instance-web and awx-instance-task but I didn’t find any issue.
How can I check this function is working? What can I do?
Does anyone have any ideas?
Thank you and best regards, H