SSRS Report not providing the data

Hi All,

I have a report which has a filter parameter as Dropdown. The number of items in the drop down may be more than 400. When I select all the items by clicking on Select All and click on 'Generate' button, the report simply posts back and does not provide the data.

But when i select only some of the items in the drop down filter, the report provides the data.

Can you please let me know the solution for this.

Many thanks