When you loaded the audience, did you target the profile?

Did you rename the alias under additional data to @email, then use @email for the join.

Why aren't you joining by Email_address?

This might help you get to where  you want to go.  It also has a example code: https://experienceleaguecommunities.adobe.com/t5/adobe-campaign-standard/preference-center/qaq-p/398260 

I copied Check URL(urlSource) and then made my mods for bit.ly checking.  It works perfectly and stops the delivery during proofing.

Our deliverability vendor is requesting we put something in place to stop the use of Bit.ly links.  We have tried educating our user base, but some just forget. Does anyone know a way to stop emails with these links from sending?  Topology rule, script, .....? 

You could probably create a real time transaction messages and target the SMS incoming message. The join would have to be both mobile and text. Then have an update in the background workflow. Worth a try.

You can create a workflow with an activity of an incremental query that monitors the resource Incoming SMS (inSMS) for a specific reply.  Then the workflow can update the profile and send an sms auto-reply.

You could make your workflow triggered by a signal activity.  Then create additional workflows to trigger it when wanted. John

It might be one of the parameters that you are passing in the Body of the Post.