LSQL with Prompts inputs not working

Summary:

I've got a combined subject area LSQL which looks at 3 possible input prompt which can be blank or filled with values by end users.

I'm passing the prompt inputs to the LSQL using presentation variables.

I've also put in the dummy filters at the end of the LSQL as I've seen being added to similar reporting setups in this forum.

However when I try to run the report, i'm getting this error;

The specified criteria didn't result in any data. This is often caused by applying filters and/or selection steps that are too restrictive or that contain incorrect values. Please check your analysis filters and selection steps, and try again. The filters or selection steps currently being applied are shown below.