gpg: keyserver receive failed: End of file
While installing ROS (step 1.3), found this issue as shown below
W: GPG error: http://packages.ros.org/ros/ubuntu focal InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY _________________
E: The repository 'http://packages.ros.org/ros/ubuntu focal InRelease' is not signed.
I tried the solution provided in this link. I deleted the old key, while adding new key (which is),
sudo -E apt-key adv --keyserver 'hkp://keyserver.ubuntu.com:80' --recv-key C1CF6E31E6BADE8868B172B4F42ED6FBAB17C654
faced a new error.
gpg: keyserver receive failed: End of file
Any suitable solution for this issue ?