If I run the query outside the stored procedure, I get results, but I only get the column names as the result after executing the query - even though return value is 0. Any help would be appreciated.

ALTER PROCEDURE [dbo].[Reconciliation2]
(
    @Param1 int,
    @Param2 int,
    @Param3 varchar,
    @Param4 varchar
)
    
AS

BEGIN
    SET NOCOUNT ON;

    SELECT 
        T.FY AS [FY],
        T.FY_PERIOD AS [Period],
        CONVERT(DATE, CREATED_DATE) AS [Created Date],
        CONVERT(DATE, TRANS_DATE) AS [Trans Date],
        T.TRAN_DOC_TYPE AS [Doc Type],
        TASK_ID AS [Task],
        T.DOC_NO AS [Doc Number],
        LINE_NO AS [Line],
        SEQNO AS [Seq],
        LINE_DESCRIPTION AS [Description],
        SUBSTRING(ACCT_NO,1,2) + '-' +
           SUBSTRING(ACCT_NO,3,5) + '-' +
           SUBSTRING(ACCT_NO,8,5) + '-' +
           SUBSTRING(ACCT_NO,13,6) + '-' +
           SUBSTRING(ACCT_NO,19,4) + '-' +
           SUBSTRING(ACCT_NO,23,4) AS [Account Number],
        DEBIT,
        CREDIT 
    FROM       
        DBVW_FIN_TRANSACTIONS_UDR T
    INNER JOIN
        (SELECT    
             INST_ID, FY,
             TRAN_DOC_TYPE, DOC_NO
         FROM       
             DBVW_FIN_TRANSACTIONS_UDR
         WHERE      
             INST_ID = 'SC00' 
             AND FY = @Param1 
             AND FY_PERIOD = @Param2 
             AND ([ACTION] = '' OR [ACTION] = 'V') 
             AND SYS_GEN_DETAIL_LINE = 0 
             AND TRAN_DOC_TYPE = @Param3 
             AND TASK_ID = @Param4
         GROUP BY   
             INST_ID, FY, TRAN_DOC_TYPE, DOC_NO) TRAN_BASE ON TRAN_BASE.INST_ID = T.INST_ID AND 
                                                      TRAN_BASE.FY = T.FY AND
                                                      TRAN_BASE.TRAN_DOC_TYPE = T.TRAN_DOC_TYPE AND
                                                      TRAN_BASE.DOC_NO = T.DOC_NO
    WHERE      
        T.INST_ID = 'SC00' AND
        T.FY = @Param1 AND
        T.SYS_GEN_DETAIL_LINE = 0 AND
        T.TRAN_DOC_TYPE = @Param3 AND
        TASK_ID = @Param4
    ORDER BY  
        T.DOC_NO, T.LINE_NO, T.SEQNO
END