Customizer/Live Preview doesn't work for Catch Store Pro

Hi, I purchased Catch Store Pro after trying the free version. The free version works great. The Pro version, the customize theme setting doesn't work at all, it gives a 500 site error. Maybe a conflict with something from the free version? The Pro version does activate and run ok, I just can't customize it because the customizer throws the 500 error. I have tried deleting the free version (by manually deleting the folder from the directory via FTP) but the error still happens. I have NOT tried looking into the database entries for conflicts. my site url: https://www.shipcollectibles.com