Impossible to publish a landing page in Marketing Cloud which updates Salesforce object record inside a loop

Question

I am trying to create a landing page in cloud page to be reached by a link in an email previously sent by a Marketing cloud Journey. The pages I built must:

• Get the email address from the email with the link clicked (request parameter)
• Retrieve the Service Cloud account records having that email (which can be more than one records)
• Update a custom field related to the Service Cloud account records retrieved above (since those records can be more than one I use a “for to do” AMPscript function) The AMPscript i used is the following

%%[

var @AccountRows, @i, @RowCount

SET @email = RequestParameter("email")

set @AccountRows = RetrieveSalesforceObjects("Account", "Id", "Email__c", "=", @email )

set @RowCount = RowCount(@AccountRows)

if @RowCount > 0 

  then for @i = 1 to @RowCount do

           var @AccountRow, @AccountId, @result

           set @AccountRow = Row(@AccountRows, @i)

           set @AccountId = Field(@AccountRow, "Id")

           Output(Concat("AccountId: ", @AccountId))

           set @result = UpdateSingleSalesforceObject("Account", @AccountId, "BlacklistDEM__c", "True")

       next @RowCount

endif

]%%

The problem I had with that AMPscript is that I cannot successfully publish the page (or it seems I could but when I Access the page I get this error:

Server error 500 - Internal server error. There is a problem with the resource you are looking for, and it cannot be displayed

Even the preview of the page does not work (it starts and never ends). Can anyone help me understand what is wrong with my AMPscript and how it should be in order to get what I described above?

Answer 1

You have an error in your for loop. NEXT @RowCount must be NEXT @i as you want to increase @i not @RowCount.

Also, you may consider to replace or not allow any ' character in the email input as this can cause your RetrieveSalesforceObjects to fail as well as per this ticket: https://trailblazer.salesforce.com/issues_view?id=a1p3A000000AUAbQAO

---

Warning:

You should re-think this approach completely as you have no validation that the call of the page is coming from an email as expected. With this setup I would be able to run a list of emails against your endpoint and update your CRM records.

A better approach would be using CloudPageURL and adding QueryStringParameters to the call and at least expect a payload which you set in the link of the email.

---

Here is your code adjusted:

%%[
    VAR @AccountRows, @i, @RowCount

    SET @email = replace(RequestParameter("email"), "'", "")
    SET @key = RequestParameter("key")

    IF NOT Empty(@email) AND @key == 'yourKeyYouDefineInTheEmail' THEN

        SET @AccountRows = RetrieveSalesforceObjects("Account", "Id", "Email__c", "=", @email )

        SET @RowCount = RowCount(@AccountRows)

        IF @RowCount > 0 THEN 
            FOR @i = 1 TO @RowCount DO

                VAR @AccountId, @result

                SET @AccountId = Field(Row(@AccountRows, @i), "Id")

                IF NOT Empty(@AccountId) THEN
                    UpdateSingleSalesforceObject("Account", @AccountId, "BlacklistDEM__c", "True")
                ENDIF

            NEXT @i

        ENDIF

    ENDIF
]%%

In your email:

%%[
    CloudPageURL('ID of your cloudpage','email',emailaddr,'key','yourKeyYouDefineInTheEmail')
]%%