Jenkins has no installation candidate : error while trying to install jenkins on ubuntu system

so im trying to install the jenkins on my ubuntu and ofc i made sure to update the system by running : apt update

then i tried to run the following commands from jenkins website to install jenkins :

"

curl -fsSL https://pkg.jenkins.io/debian-stable/jenkins.io.key | sudo tee \/usr/share/keyrings/jenkins-keyring.asc > /dev/nullecho deb [signed-by=/usr/share/keyrings/jenkins-keyring.asc] \https://pkg.jenkins.io/debian-stable binary/ | sudo tee \/etc/apt/sources.list.d/jenkins.list > /dev/nullsudo apt-get updatesudo apt-get install jenkins

then i got an error message that says :

Reading package lists... DoneBuilding dependency treeReading state information... DonePackage jenkins is not available, but is referred to by another package.This may mean that the package is missing, has been obsoleted, oris only available from another sourceE: Package jenkins has no installation candidate

i barely understood, is that trying to recognize the repo which the files are downloading from?

i saw a youtube video of someone who had the same problem and he use the following commands:

wget -q -O - https://pkg.jenkins.io/debian-stable/... | sudo apt-get key add'sudo sh -c 'echo deb https://pkg.jenkins.io/debian-stable binary/>/etc/apt/sources.list.d/jenkind.listsudo apt-get updatesudo apt-get install jenkins

but it still doesnt work for mecan you help me please get jenkins installed ?