To verify that you advert has been published, connect to your account and check the status of the advert.
Sometimes, if you are looking at search results alone, they will apparently not show your listing, but in reality, it is a long way down the catalogue.
You can check on your advert position / visibility by using the Search the sites function on your account.
Check the End of publication date on your account.
Check that you have not inadvertently taken your listing offline with the Take offline button on your account - you can easily reverse this by clicking on the Publish button.
If your listing is really not online, and your publication date is still valid, then you need to check that you have not forgotten to confirm that your property is still for sale - see Validation of your display on the sites.
Becarfull of the filter you use, for exemple if you classified your property as "prestigious demeure" it will not appear in the house research.