If I leave some activities in the background it just stopped or paused !!

Those presumably are not designed to.

You just proved that Times Radio which is designed to work in background does work normally.

Contact Dropbox or look at their forum if they have one.

PS Youtube app has two versions. You pay for the one that plays audio in background.

panos256 wrote:

If I leave some activities on the background for example if I upload a file or download in Dropbox it just stopped or paused !! Please fix this issue

iOS does not multitask as you are expecting. iPadOS does,.

AsPeter points out, some apps will have a background app refresh feature, but not all do.

Is Background Refresh turned on for Dropbox?

If so then ask Dropbox to fix their app.

Isn't that normal unless the app specifically runs that way?

Do you have any radio stations on your app store like LBC or Times Radio you can test?