Can no longer send SMS from MacBook Air and iPad
My MacBook is running OS 10.11.6 and it seems that when I did a security update last week, I suddenly can no longer send SMS via iMessage, nor can I send texts from my iPad to non-Apple users. I had been able to do this with no issues for the past year. My settings have not changed on my primary device, my iPhone. iPhone and iPad are both running 10.3.1 and the message settings are set up for text forwarding to both MacBook Air and iPad. And yes, "send as SMS" is selected. Sorry if this has already been addressed, but when I searched it said it could not find any other questions that matched mine. Thanks in advance.
MacBook Air (13-inch Mid 2011)