css - HTML email - TD hover to change back background-color not working -

My codepease:

Note that this is not for a regular webpage, I create an HTML I'm emailing, though it would be nice to not have a simple rollover color (no javascript) for modern browsers / email clients. I'm not sure why my hover is not working.

I have been using the code from the other TD Hover Stackwaveflow questions I've found so far.

  td.blue - button: hover {background-color: # 267aa6; }   
 How can you create it?   
 
 
 You take priority on inline style External  td.blue-button: hover  Used to be.  
 Check  
 Remove square  
  td .blue-button {background color: # 006497; } Td.blue-button: hover {background-color: # 267aa6; }