Hi Valerie, I am John J.D., a fellow Microsoft user like you.
I understand you're having issues with the Messenger app on your Windows 10 laptop. Let's work together to figure this out.
Since the issue seems to be happening when using another device, have you also checked if the problem occurs when using the Facebook or Messenger web version in your browser?
If the issue persists, it is possible that you are blocked from sending messages due to Facebook community guidelines. In this case, you might want to contact Facebook support for further assistance.
John J.D.