On Sunday I was able to connect my Windows 10 to my Roku stick by wireless mirroring. Tonight when I clicked on the "Connect" icon on my Windows 10 computer it states that my computer does not support Miracast and neither of my two Rokus were appearing. Has anyone else had this problem? Where it originally worked followed by not functioning? I was originally excited but now am very confused. Any help would be great.
That's a Windows 10 error message - not a Roku one
Most likely your Windows 10 install was updated (without your specific consent or knowledge) sometime after monthly updates were released on Tuesday earlier this week (known each month as "Patch Tuesday").
One or more of the updates likely broke Miracast functionality for you - and you are not alone: