Yes, they are both technically correct.
I'd say that the second one would usually be more natural in the way you might normally be using that sentence.
The 'from' gives more of an emphasis on the place it is happening.
"Are you coming to watch the game today?"
"No, I'm watching it from home tonight."
For example, "I'm calling you from the hospital", is giving the location of the person making the call.
But, "I'm calling you at the hospital", is more concerned with where the recipient of the call is - 'at the hospital'.