Landing Page conflicts with Sydney Pro

Hello. We are using the Sydney theme for all three of our new websites. We purchased Elementor Pro, to make landing pages but we are having an issue because our landing page won’t redirect. Here is the error code. Please advise on how to fix this issue as we do not want to change the theme. We did a temporary theme change to TwentyNineteen, and it worked fine. Please see below for the error. Thank you!!!

Hello there,

Do you have a link to your site to share here, so I can have a look directly?