Thanks for reaching out creation301,
Thanks for asking the Apple Support Communities about issues with Messages. We can help.
If you are sending blue iMessages, check here: If you can't send or receive messages on your iPhone or iPad - Apple Support
If you're having trouble sending SMS, keep in mind this is a feature of your cellular plan, not an Apple feature. One possibility is if you might have blocked any of these contacts previously, and unblocking them might sort things out. Block phone numbers, contacts, and emails on your iPhone or iPad - Apple Support
"Go to Settings > Phone and tap Blocked Contacts to see the list."
But, if not, your best bet would be to reach out to your cellular provider for assistance: Wireless carrier support and features for iPhone in the United States and Canada.
Reach back out and let us know if it's iMessage and the article doesn't help.
Take care.