Why do my messages fail to send on my iPhone 4s?

[iMore Question]

Why do my messages fail to send on iphone4s

On some phone numbers my iPhone 4s keeps failing to delver messages

 

[Ledsteplin]

Re: Why do my messages fail to send on iphone4s

Welcome to iMore! How do you know it fails to deliver? Do you get the red alert? If so, you might try Reset Network Settings. Go to Settings > General > Reset > Reset Network Settings. You will need to enter your wifi password back in afterwards.