Error: XXXXX is currently unavailable.

Several times when we work with different modules in DotNetNuke, the following error shows up:

DotNetNuke.Services.Exceptions.ModuleLoadException: Value cannot be null. Parameter name: connectionString ---> System.ArgumentNullException: Value cannot be null. Parameter name: connectionString at Microsoft.ApplicationBlocks.Data.SqlHelper.ExecuteReader(String connectionString, String spName, Object[] parameterValues)

The solution is easy, INSTALL AGAIN the DotNetNuke instance.

The problem is that there is no Connection String on AppSettings section of web.config file. It is necessary to have the same Connection String on both sections ConnectionStrings and AppSettings.

On AppSettings use the same format value and key:

add key="SiteSqlServer" value="Server=my.server.com;Database=mydatabase;uid=myUserId;pwd=myPassword"

Cheers!!!!