If you get an alert from iMessage Contact Key Verification
When iMessage Contact Key Verification is turned on, you might get an alert if your device detects an issue. Learn what alerts you might see and what to do next.
If iMessage Contact Key Verification detects a validation error or other issue, you get an alert in iMessage conversations with people who also have iMessage Contact Key Verification turned on. You might also get an alert in Contact Key Verification settings.
If you get an alert, it's likely for one of these reasons:
The person you are messaging turned off iMessage Contact Key Verification.
An unrecognized new device was added to that person’s Apple Account. This alert might mean that the person you are messaging has an issue with one of their devices, or that a sophisticated attacker might be attempting to eavesdrop on the conversation.
iMessage Contact Key Verification is unavailable. This alert might mean that there's a service outage or that iMessage Contact Key Verification is temporarily unavailable.
There's an issue with iMessage Contact Key Verification. This alert might mean that there's an issue with one of your devices or your account, or that a sophisticated attacker might be attempting to eavesdrop on the conversation.
If you get an alert about the contact that you're messaging
If you get an alert in an iMessage conversation that iMessage Contact Key Verification has detected an issue, you might want to stop messaging that contact until you can verify that you’re messaging with the person that you intend.
Check if your contact is having issues with their device or account (via FaceTime or other secure call, or by meeting in person).
From the alert, select Verify Contact to compare verification codes:
If the verification codes match, select Mark as Verified and update the contact information. If you no longer get the alert in the iMessage conversation and a checkmark appears next to the contact's name, you can continue messaging.
If the verification codes don’t match, you still get the alert in the iMessage conversation, or a checkmark doesn't appear next to the contact's name after you update their information, it could mean that you’re no longer messaging the person that you intend. As a precaution, you should stop messaging with that contact.
If you choose to clear the alert from the conversation, you can still find it and more details on the person’s iMessage Conversation Details page: At the top of the iMessage conversation, tap their name (or the More Info button on Mac) and then scroll down to Contact Key Verification.
These alerts appear in group conversations only if everyone in the group has turned on iMessage Contact Key Verification.
Learn how to use iMessage Contact Key Verification to verify your contacts
If you get an alert that there's an issue with iMessage Contact Key Verification
Check Settings (or System Settings) on all of your devices for alerts to update your Apple Account settings. First, address any alerts about a “Contact Key Verification Issue.” If iMessage Contact Key Verification still isn’t working, address the other settings update alerts.
Turn off Contact Key Verification on all devices, then turn it back on.
If one of your devices is causing an issue that can’t be resolved, sign out of iMessage on that device or remove it from your account.
If Contact Key Verification is unavailable, check Contact Key Verification settings again later. The issue might resolve itself.
If you can’t resolve an issue with Contact Key Verification, you might be able to reset it:
If you no longer have access to a device with iMessage Contact Key Verification turned on, you can reset it from the web: At account.apple.com, select Sign-In & Security, choose Contact Key Verification, then select Reset Contact Key Verification.
If your device is running older software, you might also have the option to reset in Settings: Go to Settings (or System Settings) > your name > Sign in & Security, then look for the option to Reset Contact Key Verification.
If you think that your Apple Account has been compromised
If you believe that your account might be compromised:
Reset your Public Verification Code: Go to account.apple.com to sign out of your Apple Account on all of your devices and change your Apple Account password: Select Sign-In and Security, then select Password. Before you change your password, select the option to “Sign out of Apple devices and websites associated with your Apple Account.”
Re-verify with contacts: If you reset your Public Verification Code, anyone who saved it will get an alert in iMessage conversations with you. These contacts need to verify you again by saving your new Public Verification Code.
Review the devices associated with your Apple Account: Go to Settings (or System Settings) > your name, then scroll down to check your devices. You can also check at account.apple.com. If there’s a device that you don’t recognize, select it, scroll down, and select Remove from account.
Learn what to do if you think that your Apple Account has been compromised