I can’t stream direct tv on my smart tv

You can't. The DirecTV app is not available for any TV or media streaming device (i.e. Roku).

AT&T TV Now is the new name for Directv Now which is a streaming only services. It has nothing to do with satellite TV (DirecTV).

So DirecTV and AT&T TV Now (formally Directv Now) are two different TV providers owned by AT&T. If you want DirecTV on that TV, you get a box and pay for that TV authorized on the service.

You can log into a networks streaming app with your DTV credentials.

I just had the same problem and after a few days of playing, I was able to get it back.  My Genie Mini is plugged into my Samsung TV via an HDMI cable.  I unplugged the cable from the tv and reinserted it.  The TV then went into "detecting device" mode.  When it finished, it called it an "unknown source" and asked me if I wanted to do a manual set up.  I chose that option.  It then had me choose what kind of device (in this case - satellite TV/Cable box), it then asked me for my zip code and finally, it gave me a list of providers in my area and I was able to choose my Directv package.  Once I did that, the app reappeared in my Smarthub and works correctly.  I hope this helps.

@dfiresto you are replying to a three year old thread that is somewhat unrelated to the original poster. They are talking about the DIRECTV app for smart TV while you are talking about the proper steps to get a Genie mini working on an HDMI input for the TV.

Closing this.