Also to know is, why would a text message be undeliverable?
Invalid NumbersThis is the most common reason that text message delivery can fail. If a text message is sent to an invalid number, it won't be delivered – similar to entering an incorrect email address, you will get a response from your phone carrier informing you that the entered number was invalid.
Similarly, how do I fix undeliverable emails in Outlook? This error typically indicates a problem on the receiving server. Try these fixes: Make sure the recipient address is valid. Reduce the number of recipients in the message. If you received this error when sending a message using Outlook or another email app, try using Outlook.com to send the message instead.
Besides, why would a text message say not delivered?
Actually, iMessage not saying “Delivered” simply means the messages has not yet been successfully delivered to the recipient's device due to some reasons. Reasons could be: their phone not having available Wi-Fi or cellular data networks, they have their iPhone off or on Do Not Disturb mode, etc.
What does a failed text message mean?
Failed means that we weren't able to successfully send your message to the delivery provider.