It is simply not unlocking or you are still having a problem opening it?
Did it open by remote, or just unlock?
Is the sheet ripped? I'd check for threads on the latch.
Not ripped, but a whole lot of sheet got caught in that mix? Possibly slightly bent latch.
Non of that should affect the unlocking though. Do you hear the motor moving but no unlocking?
Motor not moving? Check fuses, but I'm guessing the motor is moving if you're not unlocking by key also.
You would need to remove the panel that covers the interior over the handle and look for something not connected.

 

The sheet did not get ripped nor there is any thread in latch. For the first time when the sheet got caught and the remote did not work I just opened the panel from the back and open the trunk manually from the back lever. Since then when ever I try to open the tail gate it just beeps three times. And one more thing is whenever I start the vehicle the light of the truck for inside the vehicle is always on.

 

Sounds like maybe the plug for the latch got broken or just unplugged.

Side note - you have a Gen 6, selecting that in the suffix may draw others with the same generation that might be of help.

 

Side note - you have a Gen 6, selecting that in the suffix may draw others with the same generation that might be of help.

Fixed.

 

I don't know what happened with the 2020/gen 6. Maybe I was due for sleep. I read it as 2002 2nd gen as was thinking along those terms.
I don't know anything about gen 6, but the 3 beeps and light being on may have something to do with alarm / security system. I don't know that it would have anything to do with not opening mechanically by key, but these newer cars are overthinking everything.

 

I had some similar glitch once. 12V battery reconnection helped