I've tried downloading a copy of your website, but the process failed multiple times. To be able to verify the issue and test solutions, I need you to please create a staging (testing) copy of your website on the same server, so I can check for causes and solutions without harming the live website.
You can use a plugin to achieve that, or reach out to your hosting support, ad they might be able to help you creating a staging website. Please send me the link to it here, when you are done. Thank you for the cooperation on this matter.
You can keep the same user you've already shared on staging, so I can access it directly.