iMessage and iCloud accounts do not match

Hey there Simon,

Thanks for reaching out to the Apple Support Communities. To get started, from the screenshots you've provided, we did notice that you're not currently signed into your Apple ID account in the Settings app.

If you tap "Sign in to your iPhone" at the top of the Settings app, and sign into the same Apple ID as the one listed under the Messages app, are you then able to sign out and back into Messages without issues?

As for issues with AirDrop, let's ensure that all the settings are enabled and correct using this link here: How to use AirDrop on your iPhone, iPad, or iPod touch - Apple Support

Keep us updated with the results.

Take care!

Simon R,

Are you still getting the same alert now that you're signed back in or having issues with Messages in iCloud not working as expected?

If you still get the alert, try the following steps out:

1. Turn off Messages in iCloud in Settings > [your name] > iCloud.

2. Turn off iMessage in Settings > Messages.

3. Turn off FaceTime in Settings > FaceTime.

4. Restart the iPhone.

5. Turn on iMessage in Settings > Messages.

6. Turn on FaceTime in Settings > FaceTime

7. Wait 5 minutes.

8. Turn on Messages in iCloud in Settings > [your name] > iCloud.

Regarding AirDrop not working, be sure to check out the "Before you begin" section here, which may help with getting that working: How to use AirDrop on your iPhone, iPad, or iPod touch - Apple Support

Cheers.