iMessage is a messaging service offered by Apple.
“With Messages for Mac, you can send unlimited messages to any Mac, iPhone, iPad, or iPod touch that uses iMessage, Apple’s secure-messaging service. iPhone owners can use it for SMS and MMS messages, too.”
You need to use your Apple ID in order to use this service. If iMessage is not set up, a window will open asking you to sign in with your Apple ID and password.
It is important to note that you should sign in with the same Apple ID that you’ve used when you first set up your Mac. The ID should also match the one you’re using with other Apple products like iCloud, App Store and iTunes.
To set up iMessages on your Mac for the first time:
1. Open Messages from the menu bar.
2. Type in your Apple ID and Password. Click Next.
3. Because you’re logging in with the same ID that is used on your iPhone, you’ll receive a notification, asking you to verify this action. A 6-digit verification code will be sent to your phone. Use it to access iMessage on Mac.
If you have trouble signing in to your iMessages account on your Mac, try the following suggestions:
Make sure that your device is properly connected to the Internet.
Go to Apple System Status to check if the issue is not a temporary outage.
Updating your OS is vital when it comes to resolving issues with any device. Make sure your Mac is running the latest software.
Third-party software could be blocking your access to iMessage. Often, the cause is a firewall, VPN or other security software that is blocking the network ports used by iMessage. To fix this, simply disable the software in question.
Double-check your credentials. Look for typos when you type in your ID. Also, sometimes users forget they’ve turned Caps Lock ON when entering their passwords, which usually results in a failed attempt to Log in.
Another reason for your troubles with signing in to iMessage could be the Date & Time settings. From the top left corner of your display, click on Apple menu option > System Preferences > Date & Time. If the date, time and/or time zone are not correct, make the necessary changes. Alternatively, if the box next to ‘Set date and time automatically’ is checked, make sure to deselect and select it back again.