Hi I was trying to activate imessage using my mobile phone number. But its been weeks and its not letting me sign in. Can you look into it. Btw my mobile sim is sri lankan and its perfectly working now in my iphone. Its just the imessages.

Thanks for posting in the Apple Support Communities praveeeasu,

If you're having trouble activating iMessage, the following steps may provide a solution:

To use either iMessage or FaceTime, you need to activate them on your iPhone. If you see an error message when you try to activate, follow these steps.

When activating iMessage or FaceTime, you might see one of these messages:

* Waiting for activation

* Activation unsuccessful

* An error occurred during activation

* Could not sign in, please check your network connection

* Unable to contact the iMessage server. Try again.

What you need before you sign in

* Make sure that you’re connected to a cellular data or Wi-Fi network. 

* Make sure that your device has the latest version of iOS or iPadOS.

* Make sure that your time zone is set correctly. Go to Settings > General > Date & Time.

If you're using an iPhone, you need SMS messaging to activate your phone number with iMessage and FaceTime. Depending on your carrier, you might be charged for this SMS.

If a prompt appears stating "Your carrier may charge for SMS messages used to activate FaceTime and iMessage", tap "OK" to allow possible SMS charges.

Turn off and restart iMessage and FaceTime

1. Go to Settings > Messages and turn off iMessage.

2. Go to Settings > FaceTime and turn off FaceTime.

3. Restart your iPhone.

4. Turn iMessage and FaceTime back on.

If your phone number still doesn’t have a check next to it in Settings after 24 hours

It might take up to 24 hours for your carrier to verify your phone number with Apple. Contact your carrier to make sure that you can send and receive SMS messages and wait up to 24 hours after you try the troubleshooting steps above.

Use an email address to sign in to Messages or FaceTime instead

You can also use your email address with iMessage and FaceTime. Sign in to your Apple ID account page and review all the email addresses you have on file, including the one that you're trying to verify. If the email address is incorrect, you can update it. Then click Resend next to the email address that you want to verify.

To select your email address to use with Messages:

1. In the Settings app, tap Messages.

2. Tap Send & Receive, then choose your email address.

To select your email address to use with FaceTime:

1. In the Setttings app, tap FaceTime.

2. Scroll to You Can Be Reached By FaceTime At, and choose your email address.

When you use both your phone number and your email address with Messages, you might start or receive separate conversation threads with the same contacts. Set your phone number or email address as the primary way to start and receive Messages.

FaceTime isn't available in all countries or regions.

If you can't turn on or sign in to Messages and FaceTime when you try on your Mac or iPad

If you can't sign in to your iMessage account or FaceTime on your Mac

If you need more help, contact Apple Support, who have the tools and resources to investigate and assist further: Get Support

Cheers!