Several things:
You appear to be trying to use Soapi.CS -- which is way obsolete and using an old API version that no longer functions. If you are going to use .net, try one of the more recent libraries like:
This code:
.Questions.ById(1)
would fetch question #1, which has been deletedwhich has been deleted.
The API will not fetch deleted questions. When testing you need to check your requests against the site to see if they make sense.If you have problems with a 3rd-party library, that's listed here on Stack Apps, do not post the report as a question -- since the issue is not with an official Stack Exchange product.
Post such 3rd-party problems as "answers" on the libraries question page. You can see an example of someone doing that with this answer.