The Messages app on my Macbook Pro (running High Sierra) suddenly stopped sending text messages to Android devices. I can still send texts to Android users from my iPhone without a problem, but when sending texts from the Messages app on my Macbook Pro it will not send to Android devices. It just started doing this out of the blue yesterday. I have not had an issue until then. And I have not made any updates to the Mac or the iPhone OSs in that time that might cause the problem, but I did install Microsoft Office 2018 on the Mac. Cellular data is turned on on my iPhone as is Send as SMS.