Yubikey ssh on Ubuntu 22.04

Today I did full fresh installation of Ubuntu 22.04 to migrate to new 2T NVME disk from Samsung as I had disk space issues with my old 500G drive. 

After installation I noticed that I cannot use my Yubikey for ssh auth as documented here. 

I tried to add Yubikey as auth source and it failed with pretty weird error:

ssh-add -s /usr/lib/x86_64-linux-gnu/opensc-pkcs11.so

Enter passphrase for PKCS#11: 

Could not add card "/usr/lib/x86_64-linux-gnu/opensc-pkcs11.so": agent refused operation

 This error can mean literally anything.

I've tried running ssh agent manually in foreground mode:

ssh-agent -d

And after that I saw error which sounds like "no available slots".

So I back to guide as I suspected that my Yubikey died and I've sued following command:

sudo ykman list --serials

WARNING: PC/SC not available. Smart card (CCID) protocols will not function.

ERROR: Unable to list devices for connection

1232134323

That's interesting and this error lead me to this bug and I got fix:

 sudo systemctl start pcscd

After that it worked just fine.

As long term fix you need to enable automatic start on machine boot: 

sudo systemctl enable pcscd

Sadly it's known Ubuntu bug.