If you have submitted your site again and again to Search Engines but you are still unable to get it indexed, it MAY be your Web hosting provider who is responsible. To be safe its best to host with a reputed Website Hosting Provider.
Your Web Hosting provider should be up 24/7. For proper website service it must be up 100% of the time so that Users and Search Engines aren’t faced with a blank page or a 404 error.
Search engines have no specific schedules for crawling, so your website must be up at all times in order to maintain your Search Engine Ranking.
Below is a list of the Top Hosting companies in order of their rank.