I've been having issues sending and receiving messages on the samsung messaging app. This only happens when I'm texting with anyone that is also using samsung chat features. The only work around I have found is switching to Google messages. I have gone through numerous steps with tmobile tech support i even went into a store to get a new sim card but still it is not working
You can try these steps to get your text messaging working. https://www.samsung.com/us/support/troubleshooting/TSG01001439/ If the issue persists, I recommend reaching out to your service provider for additional troubleshooting assistance.