That usually happens when the site's web host does not provide a reliable uptime.
It can be safely said that uptime is the most important element about having a site.
There is no use for having a fancy website filled with information if it is not accessible by visitors half the time.
Therefore, it is important that you have a reliable uptime to be able to receive visitors at all times.
Seeing its importance, companies these days usually offer a minimum of 99.
9% uptime to their clients.
Although many hosting companies promise an impressive 99.
9% uptime, not all of them follow through with their promise.
It is difficult to find out which company is truly able to deliver such a performance as you can't tell the standard of their performance from their site simply by reading their claims.
There are some programs available that attempts to monitor the site's uptime, however, this may not always be accurate as the site it is monitoring may not be hosted on the same server that your site may be.
Therefore, there is no sure way of determining the reliability of the web host before signing up.
Users may have a better shot at finding out the true reliability of the hosting company via reviews, word of mouth, or experience.
Users could experience the web host's service first hand by trying out their trial packages if they offer any.
Trial packages allow users to use the hosting plan free of charge before deciding if they are satisfied with the plan.
If they are, they can continue with the plan, otherwise, they can discontinue it with no further commitment.
Besides trial packages, there are many review sites on the internet which users can read.
Most of these reviews are written by professionals as well as other experienced webmasters.
This way, you could have a more realistic idea on the company's performance.
If you are new to web hosting, it would be best to do some research before making any commitment to a hosting plan.
Perhaps start with reputable companies or companies that are recommended by professionals as well as friends.
Also, it would be an advantage to start with a free trial package so that you can be sure that it will serve you well.