This application is currently offline
<p>I was working(learning) with Data bound controls in ASP.Net and suddenly got the error:</p>

<p><strong>This application is currently offline. To enable the application, remove the app_offline.htm file from the application root directory.</strong></p>

<p>I started searching it on google but ended up with no helpful solution. I was not able find app_offline.htm file also. And then I suddenly tried to open my project in browser again and it opened successfully and now its working. And now I have observed that in between as I am working on the project it shows this error in between (cant say when and on what criteria) and then after some time it starts working again. Can anybody help me why its happening?</p>

<p>I am using ASP.Net4.0 and Sql Server Express Edition.</p>

<p><strong>EDIT</strong></p>

<p>With somemore searching on google it seems that this gets created automatically in the solution. If we delete it the program works fine and even if you do not delete it gets deleted after sometime by itself. but will be created again after some time.</p>

<p>Its hard to post any code because there is no code that is giving error. But when I press (ctrl+F5) to open my project its giving error. Still for reference I created a webform Review.aspx based on a masterpage. I created a combobox and a gridview inside it. Here Combobox has some collection of numbers (GenreId) and when you select a GenreId it do Autopostback and Gridview shows the entry associated with the selected GenreId. <img src="http://i.stack.imgur.com/GiEdG.gif" alt="enter image description here"></p>

<p>And then I tried to debug it in a browser, its giving error (for some time).</p>
