When SSH command update, file not found

Hello,
I’m stuck with OSMC November 2020.11-1 : it never changes with the Updates menu in My OSMC.
I tried to update with the command line.

But, when I launch the sudo apt-get dist-upgrade it appears not being able to find some file on the net (liste just beyond). And my Raspberry Pi3 is connected with Ethernet wire.

Somebody may help me ? Thanks !!!

Err :1 http://security.debian.org buster/updates/main armhf libssl1.1 armhf 1.1.1d-0+deb10u6
404 Not Found [IP : 199.232.170.132 80]
Err :2 http://security.debian.org buster/updates/main armhf openssl armhf 1.1.1d-0+deb10u6
404 Not Found [IP : 199.232.170.132 80]
Err :3 Index of /debian buster/main armhf base-files armhf 10.3+deb10u9
404 Not Found [IP : 199.232.170.132 80]
Err :4 http://security.debian.org buster/updates/main armhf curl armhf 7.64.0-4+deb10u2
404 Not Found [IP : 199.232.170.132 80]
Etc…

Make a backup via MyOSMC and do a fresh install.

Every other approach would mean quite some manual work.