I'm having some issues understanding a custom unsubscribe link that links to a 3rd party landing page.
What I would like to do is this:
<a href="%%=RedirectTo(concat('https://example.com/unsubscribe?param1=',_SubscriberKey,'¶m2=',Base64Encode(emailaddr, 'UTF-16')))=%%">link</a>
Not a single email using the inline code above arrives, even though I'm not receiving any errors in the rendered subscriber preview and the link shows 100% correct there.
What I have to do to get this link to work is the following:
%%[ var @email, @email64, @unsub, @unsub1, @unsub2 set @email = emailaddr set @email64 = Base64Encode(@email, "UTF-16") set @unsub1 = concat("https://example.com/unsubscribe?param1=", _subscriberkey) set @unsub2 = concat("¶m2=", @email64) set @unsub = concat(@unsub1, @unsub2) ]%% ... <a href="%%=RedirectTo(@unsub)=%%">link</a> ...
I couldn't find anything in the docs as to why my 1-liner would lead to errors, so I would really appreciate it if anyone could provide some insight in terms of what's happening here.
On a side note: any way to enable a more verbose error handling? Emails simply not showing up isn't really helpful trying to figure out what's happening here.