There is a major issue with your website – probably as a result of the WordPress theme. This article explains the issue in more detail: https://simple-press.com/documentation/codex/faq/troubleshooting/what-is-this-jquery-conflict/
In the case of your site, the main jQuery library is being loaded twice. The proper and WordPress standard and supported version is being loaded by Simple:Press. Immediately after that a non-standard and supported version is being loaded from the Google CDN. This is almost certainly being loaded b y your theme.
If the theme was written properly to standards and they were (a) using the correct jQuery library and (b) enqueueing it correctly, then the problem would, I am certain, be resolved. If you are not a programmer yourself perhaps you could talk to the theme developers and have them correct these issues.
And while doing that it would also be useful to ask them to ensure that the BootStrap script library they are using (another non-standard and unsupported library) be loaded BEFORE the jQuery UI library as it has a habit of causing display issues if loaded the other way around.