Messages failing to send since iOS update

Its not the service provider, iphone messages work fine, its the IOS upgrade that has caused the error. The messages ARE being transmitted to androids, the problem is the phone gives you an error message that they are Not delivered.

I have thesame issue after the IOS 15.4.2 update on an Iphone 12. The messages are Green SMS and going via cellular data,. The messages are being received by the sender but on my phone show as a message send failure/ not received.

I restarted my device and have the same issue

wifi calling is on, I have a strong wifi signal and a 4G celluar phone signal

Its just text no pictures

Its tyo one person not a group

I have lots of space on my phone

Phone number is correct and the same messages last week before the update went fine

Net the IOS update has done something to generate this error message - Please advise how to fix

Same issues as other posters

+ troubleshooting checklist did NOT fix

<Specific problem using Messages with attachments>

opened new message window & easily sent txt to same person,

but 2nd message with pdf once again "Send Fail"

Hi mhairibell,

If you'd like your messages to send without an error message, this information might help. 

You mentioned that the messages, do in fact send, but you still get the error message. Because the messages seem as if they aren't sending (even though they are), let's follow the steps here: 

1. Restart your device:

iPhone

iPad

iPod touch

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.

The information above is from If you can't send or receive messages on your iPhone, iPad, or iPod touch. If the issue remains after following the guidance above, let the community know what steps you had a chance to try. Additionally, we'll want to know if this is on Wi-Fi, cellular, or both, if this is an iMessage (blue) or SMS message (green), and if this is just happening with one contact or a few. 

We hope that helps with your question and take care!

If this is happening with only SMS messages you need to contact your cell service provider.

Turning off i-messages and then rebooting doesnt fix the problem

Hi,

All you have to do is disable iMessage, restart your device, and then turn iMessage back on again. Considering iMessage is up and running on your iPhone, first, go to 'Settings' and scroll down. Now, tap on the 'Messages' app. Right around the middle of the screen, you will see a toggle on the right of iMessage.

I understand that but problems with provisioning can occur after an update. If iMessages are working correctly but SMS are not that would show a cell service issue as SMS texts are totally within the purview of them.