SMS Error: "Invalid value specified for function parameter. Function Name: DateAdd Parameter Name: InputDate..."

Question

I'm sending 2 very similar SMSs on a journey and one of them is not working properly. When I preview it, it gives me this error:

Invalid value specified for function parameter. Function Name: DateAdd Parameter Name: InputDate Parameter Ordinal: 1 Parameter Type: Date Submitted Value: ClientID: 110008019 JobID: 0 ListID: 0 BatchID: 0 SubcriberID: 0 Data Source Type: CustomObject Data Source ID: 07e90d92-24f9-eb11-a304-48df37342d01

Since they are so similar, I don't know what could be causing the issue. Here are the codes for them:

SMS #1 (working fine):

    %%[ 
    VAR @hoje, @datalimite 
    SET @hoje = Now() 
    SET @datalimite = DateAdd(@hoje, 12, "D")
    
    InsertData("DE_TESTE_2WAY_AUM_LIMITE",DIA_ENTRADA,@hoje)
    
    ]%%

    **Other displayed text** Condicoes validas ate %%=Format(@datalimite, "dd/MM")=%%.

SMS #2 (not working correctly):

    %%[ 
    VAR @dataentrada, @datalimite
    SET @dataentrada = Lookup("DE_TESTE_2WAY_AUM_LIMITE","DIA_ENTRADA","CELULAR",MOBILE_NUMBER)
    SET @datalimite = DateAdd(@dataentrada, 8, "D")
    
    ]%%

    **Other displayed text** Condicoes validas ate %%=Format(@datalimite, "dd/MM")=%%.

I tried removing the DateAdd function and it works. I also tried displaying the @dataentrada field and it also works.

Answer 1

AMpscript function DateAdd throws the error in the second SMS because it cannot work with an empty value coming from the @dataentrada variable. In other words, your Lookup function results in an empty value and that is the problem here.

That is why your first SMS is working as expected, since the @hoje variable cannot be empty, it is always is set to reflect the current timestamp.

To cover this scenario, it would be recommended to check if Lookup brings any value and then if not - set either static fallback value for @datalimite, another way how to set this variable or change the output text to show error -

%%[

VAR @dataentrada, @datalimite, @Output_Text
SET @dataentrada = Lookup("DE_TESTE_2WAY_AUM_LIMITE", "DIA_ENTRADA", "CELULAR", MOBILE_NUMBER)

IF NOT EMPTY(@dataentrada) THEN
    SET @datalimite = DateAdd(@dataentrada, 8, "D")
    SET @Output_Text = Concat("Condicoes validas ate ", Format(@datalimite, "dd/MM"), ".")
ELSE
    SET @Output_Text = "No valid date is found."
ENDIF

]%%

**Other displayed text**
%%=v(@Output_Text)=%%

It is also easier to troubleshoot AMpscript in emails since you can preview the email without even any content and see how AMPscript would be processed.

Hopefully, it helps.