There are a few reasons why you may have received an unexpected two-factor authentication code from Facebook.
You recently enabled two-factor authentication
If you recently turned on two-factor authentication for your Facebook account, this would explain the codes. When two-factor authentication is enabled, Facebook will require you to enter a code from your phone or authentication app whenever you log in from a new device.
This provides an extra layer of security beyond just a password. If someone tries to log in as you, they won’t be able to access your account without also having access to your phone to get the code.
You’re logging in from a new device or location
Facebook may also prompt you for a two-factor code if you’re trying to log in from a new device, like a new phone, or from a new location. This is triggered if Facebook notices the login attempt coming from an IP address, device, or location that you don’t normally use to access your account.
Requiring the code helps verify that it’s really you trying to log in, not someone else trying to access your account. So if you got the login code when trying to access Facebook from a new phone, computer, or place, this would be why.
Someone else tried logging into your account
An unexpected two-factor code can also mean that someone else tried accessing your Facebook account. When they attempted to log in, Facebook sent the authentication code to you instead of the other person trying to get in.
So if you received the code out of the blue, when you weren’t trying to log in yourself, that’s a sign that an unauthorized person may have your password and tried using it to access your account. But they weren’t able to get in because they don’t have access to your phone for the second factor.
Your account was compromised
In some cases, receiving an unexpected two-factor authentication code can indicate that your account has already been compromised. This can happen if:
- You reuse passwords and one of your passwords was part of a data breach.
- You clicked on a phishing link that gave a scammer access to login cookies or credentials.
- Malware or spyware on your device stole your stored Facebook password.
In these situations, a scammer may have already gotten into your account. When they go to use it, Facebook detects the unusual activity and sends you the two-factor authentication code. This acts as a failsafe that stops them from fully accessing your account.
Your phone number changed
If you recently got a new phone number, receiving a login code can simply mean Facebook doesn’t recognize your new number. This triggers the two-factor authentication prompt when you try accessing your account.
To resolve this, you need to update your number in Facebook’s settings. Go to Settings > Security and Login > Two-Factor Authentication > Edit. Enter your new phone number and confirm it.
You still have SMS fallback enabled
Facebook used to rely on text messages for sending two-factor authentication codes. Now they recommend using an authenticator app instead, which is more secure. However, Facebook still gives you the option to keep SMS fallback enabled.
If you have this turned on, Facebook will text you authentication codes as a backup if you can’t get codes through your authenticator app for some reason. So if you weren’t expecting a code, it may be because SMS fallback was triggered.
You can disable SMS fallback in your Facebook settings if you want to stop getting texted codes entirely.
How to tell if the code is legitimate
So how do you know if an unexpected authentication code you receive is actually from Facebook and required for you to access your account?
Here are a few ways to check if it’s legitimate:
- Log in to Facebook directly rather than clicking on any links in messages or emails. Enter your username and password. If Facebook then asks for a code, it’s real.
- Look for the Facebook logo and recognized branding on the page asking you for the code.
- Check that the URL of the login page starts with https://www.facebook.com/.
- See if the code is 6 digits long. Facebook’s real codes are all 6-digit numbers.
If any of those indicators are missing and you’re not sure about the code, do not enter it. Instead, go directly to facebook.com and try logging in from there to verify the code request is real.
What to do if you get an unexpected code
Here are the steps to take if you receive a Facebook authentication code unexpectedly:
- Don’t enter the code! Going to another device, log in to Facebook directly and see if it really asks for the code.
- Change your Facebook password in case the code was triggered by someone else trying to access your account.
- Run antivirus software to check for malware or spyware on your phone or computer.
- If SMS fallback is on, consider turning it off to avoid getting unexpected texted codes.
- Check where else you reuse the same password and change it on any other accounts.
- Enable login alerts to be notified of any unexpected logins going forward.
When you need to enter the code
If you go through the steps to verify the two-factor authentication code is legitimate, here’s when you’ll need to enter it to access your Facebook account:
- When logging in for the first time on a new device
- When logging in from a new location that Facebook doesn’t recognize
- When you reuse a Facebook password that may have been compromised
- When your phone number changed and Facebook doesn’t recognize the new number
In these situations, enter the 6-digit code Facebook sent you. This will complete the two-factor verification process so you can fully log in to your account.
Conclusion
Getting an unexpected two-factor authentication code from Facebook can be startling but doesn’t necessarily mean your account is at risk. There are many valid reasons Facebook may prompt you for a code besides your account being compromised.
The most common reasons are logging in from a new device or location, having SMS fallback enabled, or because you recently changed your phone number. Less likely reasons include someone else trying to access your account or previous account compromise.
Whenever you receive an unsolicited code, verify it is legitimate directly through Facebook before entering it. Change your password as a precaution and check your login history for any unauthorized access.
Two-factor authentication ultimately provides important security. So while unexpected codes can be confusing, they help protect your account from unauthorized logins.