Well, sometimes when bootstrap studio's latest version comes some bugs give the designer problems for some time until the bugs are not fixed. Recently my student asked me this question regarding the background attachment: fixed is not working so how to make it work correctly?
So, it's amazingly simple, Remove the inline CSS which was directly applied to the body and add the following CSS
body{
background: url("imagename.png") center / cover no-repeat;
background-attachment: fixed;
}
Make sure the name of the image and extension is correct.
Just in case you want to learn Bootstrap Studio enroll in my course.
Bootstrap Studio 6.3 Course - 3 Static and 1 Dynamic Project