Emails stuck in queued

Hello.
I have nopcommerce store, I set a default account and tested it and it works fine.
I also checked that the scheduled tasks are active but no mail is sent.

When I requeued a message I get an error:
Error sending e-mail. Mailbox unavailable. The server response was: Unknown user

I'm using hmailserver and nop 3.8.

how can I make the email system worked?

Thanks in advance - Tal.

You need to configure your Email Account, and make sure you are correctly logged in to your SMTP server.

Hi, Thanks.
If I can send test email, Isn't it shows that the email is configured correctly?

Yes, if you can send test emails, then your configuration is correct. However, you if had already queued emails with a bad email account, then those will continue to fail.

Are you able to send new (non-test) emails successfully?

The issue could be that you had a bad account, and the system associated those emails with that account. If you then go delete the account and create a new good account, only new emails will use the good account. All the ones already in the queue will continue to use the bad account.

The solution for next time is to edit the existing account instead of replacing it with a new one.

At the end it was a silly reason.
I have hMailServer and my domain was defined but not the specific user so I got an error.

Thanks for all the help :)