I know this question was asked a long time ago, but recently i had the same problem so i thought i'd add my answer if anyone else comes across this. My one friend received all of my messages, but i couldn't receive any of hers. We tried resetting our network settings and everything! It turned out i had her number blocked on my phone even though i know for sure i never blocked her number. So if you tried everything else and it doesn't work, go to imessage and see if their number is blocked. I honestly don't know how it got blocked since i didn't do it, but maybe there is a glitch or problem or something that blocks some people's numbers from your phone.

Are you not receiving sound/audio notifications for iMessage? Check that your device isn't set to Silent Mode or Do Not Disturb. Both modes would silence phone calls as well as app notifications. The first thing you should always try when having issues is a hard reboot. Press and hold down the On/Off button on the right side (iPhone 6 or later) or top (all other iPhones, iPods, and iPads) of your device. While continuing to hold the On/Off button, press and hold the Home button on the front of your iPhone, iPod touch, or iPad.

Jan 2, 2017 2:23 PM

Try these steps first

1. Restart your device:
2. Check your network connection. To send a message as iMessage or MMS, you need a cellular data or Wi-Fi connection. To send an SMS message, you need cellular network connection. If you turn on Wi-Fi Calling, you can send SMS messages over Wi-Fi.
3. Check with your carrier to see if the type of message you’re trying to send, like MMS or SMS, is supported.
4. If you’re trying to send group MMS messages on an iPhone, go to Settings > Messages and turn on MMS Messaging. If you don't see an option to turn on MMS Messaging or Group Messaging on your iPhone, then your carrier might not support this feature.
5. Make sure that your device has enough space to receive images and videos.
6. Make sure that you entered the correct phone number or email address for the contact.

If you see a Waiting for Activation alert, learn what to do.

If you still need help, find your issue below to learn what to do next.

If you see a red exclamation point

If you try to send a message and you see with an alert that says Not Delivered, follow these steps:

1. Check your network connection.
2. Tap , then tap Try Again.
   
3. If you still can’t send the message, tap , then tap Send as Text Message. Messaging rates may apply. Contact your carrier for more information.

Not Receiving Imessages From One Person

If you see a green message bubble

If you see a green message bubble instead of a blue one, then that message was sent using MMS/SMS instead of iMessage. There are several reasons for this:

• The person that you sent the message to doesn't have an Apple device.
• iMessage is turned off on your device or on your recipient’s device. To check if iMessage is turned on for your device, go to Settings > Messages > iMessage.
• iMessage is temporarily unavailable on your device or on your recipient’s device.

Learn the difference between iMessage and MMS/SMS messages.

If you receive messages on one device but not the other

If you have an iPhone and another iOS device, like an iPad, your iMessage settings might be set to receive and start messages from your Apple ID instead of your phone number. To check if your phone number is set to send and receive messages, go to Settings > Messages, and tap Send & Receive.

If you don't see your phone number, you can link your iPhone number to your Apple ID so you can send and receive iMessages from your phone number. You can also set up Text Message Forwarding so you can send and receive MMS and SMS messages on all of your Apple devices.

If you have issues with a group message

If you’re in a group message and stop receiving messages, check if you left the conversation. Open Messages and tap the group message. If you see a message that says you left the conversation, then either you left the conversation or you were removed from the group message. You can rejoin a group message only if someone in the group adds you.

To start a new group message:

1. Open Messages and tap the Compose button to start a new message.
2. Enter the phone numbers or email addresses of your contacts.
3. Type your message, then tap the Send button .

If you have other issues with a group message, you might need to delete the conversation and start a new one. To delete a group message:

1. Open Messages and find the conversation that you want to delete.
2. Swipe left over the conversation.
3. Tap Delete.

When you delete a message, you can't recover it. If you want to save parts of a message, take a screenshot. To save an attachment in a message, touch and hold the attachment, tap More, then tap Save.

Not Receiving Imessages On Ipad

Learn more

Not Receiving Imessages On My Mac

• If you still can't send or receive messages, contact Apple Support.
• If you don't receive SMS messages, contact your carrier.
• If you switched to a non-Apple phone, learn how to deactivate iMessage.
• Learn how to report unwanted iMessages.