Trans Fail Safe can come up from many many different things.
Even a low battery can bring this error message out.
Like stated above, have your car codes read and see what has been saved in the memory.
If no codes are found, it could be a random glitch that does sometimes occur.
Normally, when I get the TFS, I will turn off the car for a few minutes, then restart and go. If the TFS comes back right away, stop and inspect. If it doesn't come back, could have just been a slight glitch.
But like I said, a low battery could cause this as well.