If your home is offline and this was not the result of an action on your part, it is most likely because your listing is less than 80% completed. Only a listing that is at least 80% completed can be put online and appear in the search results.
To help you complete your listing to 100%, you can read this article.
Also note that if your response rate is below 80%, your home will be online but it will not appear optimally in the search results. Please refer to this article to understand how the response rate works and how you can increase yours.