Hello Nagababu,
I think perhaps the input parameters you are using needs some tweaking. I am including a screenshot with an example below. It is important to send in the right Column Name for the search. My example is using hard coded string but you can add debug statements before the call to ensure you are iterating through the elements in your Collection A as well as specifying the right Column Name as you search through Collection B.
Hope this helps.
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Wing Ling Leung
Senior Product Consultant
Blue Prism Professional Services
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