Suspicious « app installation blocked » pop up and Tech support email

I received this pop up message all of a sudden. I never downloaded any APK or unknown app(I barely use this device as it’s my secondary device). I also received an email stating that my device has potential issues and a tech support agent would like to help me out. Is this a scam, if yes is it a mere coincidence that the pop up message and the email came the same day? Could this be an elaborate scam trying to gain access of my device?

What actions should I take?

Additional info- 1. I received the pop up again . 2. The message is not shown any website . Since It’s a device message , I suspect there something sketchy going on. 3. O.S- Android

Image Transcript- Can’t install app from unknown source

Auto Blocker is on. To keep your phone safe, you can only install apps from authorised stores.