i store some information in my website (mvc3-.net4-iis7) by this syntax:

```
HttpContext.Current.Application.Add(appKey, value);

```

and read data by this one:

```
 HttpContext.Current.Application[appKey];

```

it works fine but after a short time (about 20 minutes) it works not and can not find [appKey],i want to know
has it some setting to do or has it expire time?

i change my cookie expire time to 7 days in my web.config but not working yet.

thanks for your helping