Receiving Error 500 when attempting to display fields on CloudPage while using the UpdateSingleSalesforceObject

Question

I am getting the Internal Server Error 500 when using the UpdateSingleSalesforceObject on a CloudPage while attempting to retrieve and output Salesforce Fields such as 'Email' and 'FirstName' from a known contactKey found in SalesForce. When I run the block of code below without attempting to output the fields 'Email' and 'FirstName' the code results in displaying a count of the number of records found. Both Salesforce and SFMC are connected via the connector. Is there anything in this code that would prevent displaying of SF field data from within Marketing Cloud? What about any special permissions needing to be enabled? Are there any needed to display fields?

%%[ var @cntr, @rowset, @row, @numberOfRows, @id, @email
    Set @rowset = RetrieveSalesforceObjects("Contact","Id,Email,FirstName","Id", "=","0033h00000k2sBYZZZ")
    set @numberOfRows = RowCount(@rowset)
    IF @numberOfRows == 1 then
    set @row = Row(@rs, @cntr)
    ]%%
Email: %%=v(Field(@row, "Email"))=%%:<br>
FirstName: %%=v(Field(@row, "FirstName"))=%%:<br>
Total Records: %%=v(@numberOfRows)=%%<br>
%%[ endif ]%%

Answer 1

Looks like you intended to loop through the results. Here's how I'd approach it -- though you'll likely never have more than one row on the retrieve of a Contact by Id.

<script runat="server" type="text/javascript">

Platform.Load("core","1");

try {

</script>


%%[ 

set @rowset = RetrieveSalesforceObjects("Contact","Id,Email,FirstName","Id", "=","0033h00000k2sBYZZZ")
set @numberOfRows = RowCount(@rowset)

if @numberOfRows > 0 then

  output(concat("<br>numberOfRows: ", @numberOfRows))

  for @cntr = 1 to @numberOfRows do

        set @row = Row(@rowset, @cntr)
        set @Email = field(@row, "Email")
        set @FirstName = field(@row, "FirstName")

        output(concat("<br>Email: ", @email))
        output(concat("<br>FirstName: ", @FirstName))
      
  next @cntr

endif

]%%


<script runat="server" type="text/javascript">

} catch (e) {

    Write("<br>e:", Stringify(e))
}

</script>