user10130: I was playing chess on an app against a computer, and I could make an en passant after a move from me and the computer.

   
   [FEN ""]
   1.e4 h5 2.e5 f5 3.a4 a5 4.exf6 exf5 {Ignore the weird Bishop if you go back in the game. The parser is confused.}
   
   
Is this possible?
Can the pawn at e5 take the pawn at f5 now after a move each (o more) from the player?

user70: No. You can take a pawn en passant only on the next move.
See 3.7d, here.

A pawn attacking a square crossed by an opponent’s pawn which has
  advanced two squares in one move from its original square may capture
  this opponent’s pawn as though the latter had been moved only one
  square. This capture is only legal on the move following this advance
  and is called an "en passant" capture.


10130: <p>I was playing chess on an app against a computer, and I could make an en passant after a move from me and the computer.</p>

<p><pre>
   <code>
   [FEN ""]
   1.e4 h5 2.e5 f5 3.a4 a5 4.exf6 exf5 {Ignore the weird Bishop if you go back in the game. The parser is confused.}
   </code>
   </pre></p>

<p>Is this possible?</p>

<p>Can the pawn at e5 take the pawn at f5 now after a move each (o more) from the player?</p>
 70: <p>No. You can take a pawn en passant only on the next move.</p>

<p>See 3.7d, <a href="https://www.fide.com/FIDE/handbook/LawsOfChess.pdf">here</a>.</p>

<blockquote>
  <p>A pawn attacking a square crossed by an opponent’s pawn which has
  advanced two squares in one move from its original square may capture
  this opponent’s pawn as though the latter had been moved only one
  square. <strong>This capture is only legal on the move following this advance</strong>
  and is called an "en passant" capture.</p>
</blockquote>
