Unable to sign into Yahoo using a passkey

This is confusing. Yahoo doesn't allow passkeys. I'm not too interested in, "well technically they do..."

I think because Yahoo.JP (Japan) was one of the first companies who supported Passkeys, Yahoo was recognized to take place on the list of supported Passkeys sites.
U fortunately other Yahoo countries dit not follow this innovating initiative.
See also https://web.dev/case-studies/yahoo-japan-passkeys

Hello everyone,

Passkeys.directory now shows that Yahoo.com supports both Sign in with passkey and Passkey MFA. Please see our entry for more details: Yahoo.com - Passkeys.directory

If you don't see the option to add a passkey then it may not yet be available for your Yahoo account, it looks like Yahoo is performing a staged rollout. If Yahoo does make passkeys available for your account then 1Password will be ready to save and sign in using that passkey.

@WGBeekhuis

According to passkeys.directory, currently only Yahoo.com and Yahoo.co.jp have introduced passkey support.

-Dave