New Post: SPServices.SPFilterDropdown Error

I am not sure why my code is not working. I have searched through the other discussions and believe that my code is correct and I am still receiving an error

"Error in function
SPServices.SPFilterDropdown
Parameter
relationshipListColumn: Title
Message
Not found in relationshipList Operational Period
Click to continue""

My setup is two lists and I want to filter the value based on a choice column. In the relationship list I have two fields one is the Title Column, renamed to "Operational Period" and the other is the choice column "Show in Dropdown?"

In my current list the lookup column (also a site column so that I can reuse the code) is named "Operational Period".

Here is the code.

<script src="//ajax.googleapis.com/ajax/libs/jquery/1.11.0/jquery.min.js"></script> 

<script language="javascript" type="text/javascript" src="http://beach/SiteCollectionDocuments/jquery.SPServices-2014.01.min.js"></script>

<script type="text/javascript">

$(document).ready(function() {
$().SPServices.SPFilterDropdown({
  relationshipList: "Operational Period",
  relationshipListColumn: "Title",
  columnName: "Operational Period",
  CAMLQuery: "<Eq><FieldRef Name='Show in Dropdown?'/><Value Type='Text'>Yes</Value></Eq>",
  completefunc: null,
  debug: true
});
});

</script>

Could the reason that this is not working be because the lookup column is a site column?

Thank you for your help