Mail landing strait in the trash bin

Some of my mail regulary landing in the trash,not even in the junk.
How to mark the sender as reliable?
Brgds. Navirodof

Is it possible that the server is deleting the messages? If it is, you will need to check any server-side filters. Or maybe even another device connected to the same account?

If it is eM Client that is deleting them, then the only way it could happen is if you created a Rule to delete messages from that sender. Go to Menu > Rules and edit any you have created. It will not be a Spam or Blacklist Rule, as that would move the message to Junk, not Trash.

Thank you so much your effort about my problem.