Comment 3 for bug 1971158

Could the problem be something else? Adding the old algorithm to the configuration did not help me.

Example in config
Host old-host
    HostkeyAlgorithms +ssh-rsa
    PubkeyAcceptedAlgorithms +ssh-rsa

And try with cli options
ssh -vvv -X -oPubkeyAcceptedAlgorithms=+ssh-rsa -oHostkeyAlgorithms=+ssh-rsa dual
debug1: load_hostkeys: fopen /etc/ssh/ssh_known_hosts2: No such file or directory
debug3: order_hostkeyalgs: no algorithms matched; accept original
debug3: send packet: type 20
debug1: SSH2_MSG_KEXINIT sent