3rd Party Web Application won't run in Edge Beta

If the application relies on ActiveX controls, that is likely the reason it works in Internet Explorer but not in the new Edge browser. While Edge's Internet Explorer mode is designed to improve compatibility with legacy applications, some sites may require explicit configuration to run in IE mode. You can try adding the site to the IE mode site list or enabling IE mode through your organization's browser policies. It's also worth checking with BST Global to see whether they have an updated version of the application that supports modern browsers. If the application depends heavily on legacy Internet Explorer technologies, additional compatibility settings or vendor updates may be required for it to function correctly in Edge.