The kernel tree for 5.11 has been marked EOL. There will be no further updates to this tree. 5.11.x packages will be removed within one week. Please upgrade all systems currently using 5.11 to use 5.12: (5.12.6 is the latest as of this post)
apt-get install linux-image-5.12.6-amd64-vanilla -y
JCCHOME Linux supports LTS kernels, the newest of which is currently 5.10 and the latest mainline kernel which is currently 5.12.