Nice to see, that you are still trying.

First thing please share the code either screen shot of the widget or use Insert?edit code sample feature of community like in below Image. Because it's very difficult to understand the code.

I don't know exactly why it is not working, though it is working in my system. I have used this many time.

Now kindly share me the complete screen shot of the Footer widget. Make sure it should contain all scripts.

So I may help.

Here is the link of how to use this this model window in service portal, feel free to check this out.

https://serviceportal.io/modal-windows-service-portal/