MacOS 14.5, Firefox
I’m new to Yubikeys.
I have pieced together how to set up my Yubikey 5C NFCs with Yubikey, allowing me to successfully add 3 of them to Bitwarden. After logging out, when I try to log back in I get the MacOS prompt and choose security key. Pressing the button on the first one says that it hasn’t been set up. For the second (set up identically), I was asked to enter the PIN, reinsert and repress the button, but got “No credentials found…”
Help!
@Jz0000 Welcome to the forum!
Congratulations!
Is there a particular reason to set them up as “Yubico OTP”? Because if not, the FIDO2-“passkey”-2FA would be the better choice with the YubiKeys…
PS: Even Bitwarden recommends that in the Yubico OTP section in the Help Sites:
It sounds like you may have (accidentally) set up a passkey in your Two-Step Login configuration. I don’t believe you should see the above macOS prompt at all unless Bitwarden is trying to get a passkey input.
Please log back in to your Web Vault, go to Settings > Security > Two-Step Login, and see if there is a small green 
next to the “Passkey” option, like this:
If so, you need to click Manage and delete any passkeys that were accidentally enabled. If you have no more passkeys, you should be able to use Yubico OTP for 2FA (provided it has been properly set up).
If you still have some passkeys that you wish to keep, then you should still be able to use Yubico OTP if you cancel the macOS passkey prompt, and then clicking Select another method on the Bitwarden Two-Step Login screen:
You will then see a pop-up prompt (“Select two-step login method”), where you should be able to select “Yubico OTP”.
On the other hand, @Nail1684 brings up a good point: Why do you prefer the all-but deprecated Yubico OTP method over the more secure Passkey (WebAuthn/FIDO2) method for setting up your Yubikeys as 2FA for your Bitwarden login?
Because I’m clueless! 
Thanks, I will try the suggestion.
Thanks @Nail1684, I figured out that I needed to enter my pw before OTP. Moving on…
I’m trying that (MacOS 15.4, Firefox, web vault), but I run into:
There was a problem reading the security key. Try again.
Trying again (many times) doesn’t help.
In the help page, it says:
Some devices, including those with Windows Hello or macOS devices that support passkeys, are native FIDO2 authenticators that will offer these options as defaults. If you want to register a security key or other authenticator, you may need to select a Try another way, Other Options, or Cancel button to open up your other options.
Is this the problem?
None of those three buttons are on the popup window for configuring passkeys. Nor are they on the “Two-step login” tab under it.
Any suggestions?
Should I set it up with Windows 11 or Android? If one of those works, should it then work with my Macs, my primary desktop/laptop computers?
It is difficult to understand what exactly the problem is, without the ability to look over your shoulder at your computer screen. If you can post screenshots of what you are doing to enable the Yubikeys as 2FA, and what you subsequently see when you try to log in, that would help.
Setting this up in Windows 11 would also help, because in that case, I could show you screenshots of what you should expect to see.
(only some comments, as @grb’s suggestion - to have screenshots - would really make it easier)
Probably stupid question: but did the YubiKey in your USB port began to blink? And did you touch it?
… here we come to screenshot topic again. What did happen after you clicked “Read Key”? Did any dialog open? If yes, what did it show?
You can set it up - in the web vault - on any device you want. If it’s set up, it should work everywhere (on supported devices). - BTW, if you use the Mac desktop app, make sure it is on a current version, as FIDO2-2FA support was only added recently to that app.
Yes 2x.
No dialog or new window, just “There was a problem reading the security key. Try again.” to the right of the Save and Close buttons.
Apparently not, because I could add my keys using the web vault in Windows despite it not working on my Mac.
Now, I have:
Just to be sure: with FIDO2-2FA-“passkeys”, you can’t choose “Log in with passkey” in this dialog! You have to login with your email and master password, and then you get asked for your 2FA (= that should be the FIDO2-2FA-passkey now).
(“Log in with passkey” is a thing that has to be set up another way!)
Hm… MacOS seems to be a bit “difficult” in that regard.
Yeah, that does seem right, when there is the tick for “Passkey”. 
Yeah, in general, for the YubiKey a choice that sound like “security key” is the right one!
First, you haven’t shown us how you added your Yubikeys as a Two-Step Login provider for Bitwraden, but let’s assume that was all done correctly.
As @Nail1684 hinted, you cannot click Log in with passkey on the Bitwarden login screen — which is what you attempted (as we can see in your screenshot), and the reason that your keys “don’t work”. Instead, upon entering your email address, you must click Continue, and then enter your master password and click Login with master password. Only then will you be prompted for two-step login (using your security key).
Remember, in “Two-Step Login”, the first step is always your master password (or “Login with Device”), and the second step is your Yubikey (or OTP code, etc.).
There’s plenty of misconfiguration that could still be present, and would only be revealed by clicking Manage…
As always, you are right in the end. 
(I should have been more cautious with my statement - and at least should have written “that does seem right in general”…)
Got it. Thanks to both of you.
Just FYI, I was trying to post more screeenshots but the forum software limited me and eventually, told me to go away for 18 hours.
Your account is still in the “new user” status, which has the most limitations. To graduate to “basic user”, you just need to spend a little time reading several other threads on the forum (to date, you have only viewed 3 topics). This should lift the most severe restrictions, and also unlock your voting rights for the Feature Request category.
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