Why isn't my slider filling up the screens width?

1
Width limitation on the slider's container

By default if you put down an HTML code, it can be just as wide as the container it is in. We have a force full width option, which is a JavaScript code calculating the area left and right to the slider, and it gives negative margin to the slider to make it as big, as it has to be to reach the sides, but that has its limitation too. You could try the Adjust slider width to parent selector using an element that is surely 100% wide, like the body tag.

If it doesn't work, you will need to create a new module position or modify the CSS code of your template, so that every container of the slider would have 100% width. If you are working with WordPress, try the PHP publishing method.

2
Overflow: hidden on the slider's container

It's also possible that the slider size was calculated correctly, but one of the slider's container has an overflow: hidden CSS code and a limited width, which prevents you from actually seeing the slider where it would be outside of this container. You should inspect the codes that are making your slider's parent elements, find this code and remove it.