What is wrong with ddebs.ubuntu.com
Solution 1:
This is a current bug, see here for info and workaround: https://bugs.launchpad.net/ubuntu/+source/ubuntu-keyring/+bug/1920640/comments/3
Quoting from the above post, run:
$ sudo wget -O- http://ddebs.ubuntu.com/dbgsym-release-key.asc | sudo apt-key add - $ sudo apt update
Solution 2:
You have to follow the https://wiki.ubuntu.com/Debug%20Symbol%20Packages precisely.
You probably missed the following step:
sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys F2EDC64DC5AEE1F6B9C621F0C8CAB6595FDFF622
Then run sudo apt update.