How to delete all queued messages

[gianluigi1982]

I'm trying to delete all queued messages in mail server.
I tried using the queue tab and delete all button, but it doesn't work.

Does anybody know a way to force to delete in some way?

Thanks,

[gianluigi1982]

I can't find a way to delete those messages, so I decided to remove mail server app and reinstal it.
It works for the queued messages, but a new issue appeared.

Now I can't setup alias: when I click on the alias tab, and try to add a new on I can't see the registered user to link the alias to.

Any help?