I have this exact device!
The activation process can sometimes take a few days or so, if it's been longer, try each of these following options until you get success! You may have to repeat some of these steps, but hopefully one of them will get things working for you!
- 1st of all, definitely try closing out of the Messages app completely by double clicking your home screen button (when on that screen), until a pop up of all your open apps appears. Lift up until the iMessage tab is gone.
Restart your iPad, then re-open the app from the home screen and re-close it properly, then open it again.
- Restart your iPad by holding both the power button and the home button at the same time for 5 seconds and releasing when the white Apple Menu pops up, then check again.
Note: some of the following solutions may require this step.
Options Available in your iPad's Settings App;
1: Make sure that your internet connection is stable (by trying to load a webpage on Safari,) for the whole duration of the iMessage setup process, as iMessage relies on active internet connection unlike traditional cell phone messages. Refresh your connection under the "Wifi" department of your Settings by turning it off then switching it back on from your cellular data. You may have to repeat this process in between checking with the iMessage app status. If you are using a VPN, disable it before continuing set up. See if enabling Airplane mode fixes the message issue as well.
+ Check this website - Apple - Support - System Status - Apple's Server to make sure there's a green dot beside iMessage to make sure there isn't an outage on their end.
2: Sign out of your Apple ID, and then back into it again by tapping on your name at the top of the Settings menu. Make sure that iCloud sync us turned on for iMessages. You'll also want to check your Facetime and iMessage statuses, but we'll get to that below...
Visit the "Send and Receive" section of your ID account, tap and uncheck your phone # (make sure it is your correct # that includes your Country Code, if not, update that field accordingly,) and select "send using your AppleID" instead of your phone # by making sure the checkmark is by that, not your #, or vice versa depending on what your screen looks like. You may have to turn off iMessage, look in your accounts available for iMessage, select your phone#, log out of your Apple ID, close the app, restart your iPad to finally sign back into your AppleID again.
3: Under "General" Settings, you could "Check for Updates" - sometimes a due update can cause loads of weird issues, but if you have content you'd like to save on your iPad, I recommend performing an iTunes or iCloud backup before this step.
4: While still under "General" settings, go back one page and scroll down to "Date & Time" - make sure that the date and time on your iPad are correct by enabling "Set Automatically" toggled to green if it was grey.
5: Scroll farther down on the main Settings menu, and under "Messages", make sure that "iMessage" is turned on - (it will be green, not grey, when it's enabled). If it was already green before you opened the page, turn it off (to grey) and wait 5 minutes before toggling it again to the green. Click "ok" for any pop up message enabling this might give you.
Also make sure that FaceTime is also running, as the 2 services are interlinked. Ensure that in both programs, your phone# has a checkmark beside it at the "You can be reached" section, if not you'll have to turn off your number from this to your AppleID or in the iMessage app, sign out of your Apple ID, sign back into it and check the settings to see if it's enabled now. Once both are enabled, restart your device and check again that both options are enabled, and then test!
Alternatively, you could turn both features off, restart your device, and then go back and turn them back on.
I really hope this helps!
If it doesn't, let me know, I can post more - just exceeded the 5000 character limit for this post.
