Modeling Issues with Aperture Coupled slot antenna

Hello,

I am trying to simulate a slot antenna design from Shaker Alkaraki. The dimensions were all calculated in the article however my implementation is different as I supposed to use an aperture coupled form of it. From what I understand, this is an indirect contact method meaning the excitation will come from the feedline into the slot and into the patch. However i am struggling to simulate the results. I am not sure if this is just an HFSS issue but here is my design:



I am not confident in my edge coupled feed as, after looking through what seems like everywhere, I cannot find a similar design to this. This is the error I get when validating/simulating:
Can someone help me understand how to design this properly? I can provide more information if needed. Thank you.