Why would some reports using the SSRS ReportViewer Web control not render while others do?

Question

All of the reports I have on our SSRS server work great through the SSRS ReportViewer web control but I have 2 reports that will not render. I fill out the parameters and the page refreshes with nothing. No loading gif, no toolbar, just the parameter controls.

I have tried using the ReportViewer on Chrome, Firefox and IE. All reports but these two certain reports work great.

I've tried the methods listed in:

SSRS 2008 R2 - SSRS 2012 - ReportViewer: Reports are blank in Safari and Chrome
Only 2 reports out of >10 fail to render on SSRS 2008R2 SP2

Does anyone know why certain reports may not display while others will?

Update: I have found that if I pass in a test parameter, the report will render with 0 results. However if I pass in a valid value, I get nothing.

Answer 1

Turns out to have been a couple of things.

1. First was something to do with the query. One of the parameters accepted values with commas in it and when changing the values to not contain commas, the report worked fine. This might have been attributed to how the values were being passed to the parameters.
2. The DIV containing the report needed overflow: auto; added to it's styles.

Answer 2

I assume you are on SSRS 2008 r2. While I'm not familiar with using the web version of ReportViewer (I always preview my reports in Visual Studio), I have found that if my Data Source loses its connection string this can happen.

Do you have visual studio with SSRS? If so can you open your report there and preview it?