Marketing Cloud - Ampscript code update help

Question

We have the below AMPScript that works almost perfect. The only issue is when it fails to generate a unsubscribe link, it defaults to preference center URL. We have a custom unsubscribe managed outside of Marketing Cloud so the profile centre URL doesn't work. What do we need to update so that if the unsubscribe fails to generate it outputs our generic preferences page rather than the current dynamic unsub URL Eg: outputs URL https://website.com/preferences

Thanks Andy

%%[
VAR @globalPrefData, @Contact_ID, @emailID, @emailName, @prefCorName, @prefName, @firstName, @Greeting, @unsubscribeKey, @unsubscribeLink, @unsubscribeURL, @rowSet, @channelName
/* Global preferences data extension */
SET @globalPrefData = "SFReportGlobal" 
/* Unsubscribe link without personal unsub key */
SET @unsubscribeLink = "https://website.com/EmailUnsubscribe?id="
SET @channelName = "Events"
SET @Contact_ID = _SubscriberKey
SET @emailID = _emailid
SET @emailName = emailname_
SET @prefCorName = IsNullDefault(Preferred_Correspondence_Name, "")
SET @prefName = IsNullDefault(Preferred_Name, "")
SET @firstName = IsNullDefault([First Name], "")
/* Greeting selection */
IF @prefCorName != "" THEN 
 SET @Greeting = ProperCase(Trim(@prefCorName)) 
ELSEIF @prefName != "" THEN 
 SET @Greeting = ProperCase(Trim(@prefName)) 
ELSE 
 SET @Greeting = ProperCase(Trim(@firstName)) 
ENDIF 
/* Checking test SK */
IF Substring(@Contact_ID,1,3) != "005" THEN
SET @rowSet = LookupRows(@globalPrefData,"18 Digit SF ID",@Contact_ID,"Channel Preference Setting: ChannelPreference",@channelName)

/*New Code Starts here*/
set @count = RowCount(@Rowset)
if (@count > 0) then
/*New Code ends here*/

SET @unsubscribeKey = FIELD(ROW(@rowSet,1), "Unsubscribe Key")
SET @unsubscribeURL = Concat(@unsubscribeLink,@unsubscribeKey)


/*New Code Starts here*/
endif
/*New Code ends here*/

ELSE
SET @unsubscribeURL = profile_center_url
ENDIF
]%%

Answer 1

I'm a bit confused, if you don't want the user to ever be directed to the profile center url, then why are you using it as a fallback unsub url in your code for all SubscriberKey's beginning with "005"? Seems like it would just be safer to assign that to the generic preference center (even if you set up your Skey's such that only test users begin with 005) in order to make sure no one is ever sent to the profile center url by accident.

You'd need to update that last unsubscriberURL variable assignment to direct to another URL in order to remedy this. Also, you need assign an else statement for the portion that checks the rowcount returned from the LookupRows function. If there are no rows found, then you'd want to assign the unsubscriberURL value to match the generic preferences page list in your question above.

You may also want to check that final value for unsubscriberURL where rowcount > 0 just to make sure it isn't NULL, so you can redirect to the correct location in the event it found a row but couldn't pull a specific value from it.