- Only a few users ( especially from the same group ) users only receive Digest email
- When I tried to test the preview Summery and sent the result to email, the status shows sent, but mail is not received
Any suggestion to debug this ?
There are so many variables here, so not a lot to go on with respect to knowing how to help, but a good first step would be you shared more information on your specific configuration of Discourse and email setup, then we can better help. Also be sure to check out: Troubleshooting email on a new Discourse install. It has helpful tips for old installs too.
That said, regardless of the setup, the best first place to look at is the logs. Check the email logs in Discourse and logs on your specific email provider (if they have). Also check your other logs and try different emails to test and receive the summary. But still, if you want more help, share more details.