What do you mean by "isn't reportable"? What's wrong with it?

The syntax "USE @DatabaseName" isn't valid. You can't provide a variable as part of a statement, you'll need to use dynamic SQL.

Considering, however, that you're doing...

Could you have a look at the SSRS logs, see if it's showing anything in there in regards to your report.

Without consumable sample data or DDL, this is a guess and untested, however, maybe:
SELECT s.AILMENT_NAME, AAs.[Status]
FROM tblAILMENT A
  JOIN tblASSESSMENT-AILMENT AA ON A.AILMENT_ID =...

Thanks for the edits. I've editted my post a couple of times, but you won't get a subscription for those so I'm posting again. Have a look at my comments...

What is your question here? You haven't asked one. Questions end with a Question Mark (?), where as you have simply made a statement that you want to use a...

The problem isn't IE11, it's that your SSRS instance is set to time out the query after 2 minutes. As your report is taking more than 2 minute to run...

We are missing a lot of information here. We don't have any details on what your DDL looks like at either end, or what the query being used is to...

The guide explains how to force the type of application can connect. Also, note that if you're in Single User, do not expand any of the menus, just open a...