Error updating May

You have to describe how you are attempting to do this if we have any chance of figuring or why it’s failing.

I have tried several methods:

  1. in program- my osmc addon I have written the license directly in its apart
  2. in program- my osmc addon I have edited config.txt and add new line with "decode_MPG2=XXXXXXXXX

In both cases negative result

Finally I tried to download the config.txt and edit it in my pc but I have no permission to modify it, so could it be a problem of permission and that’s why it cannot be modified?

Have you verified it is the right licence for the device?
Provide logs with grab-logs -A

I assume you use a program like winscp. The files in /boot can only be written by root. So if you manually want to change it either copy to /home/osmc with winscp and then login with ssh and move it with sudo mv.
Alternatively just ssh in and change it with sudo nano /boot/config.txt

this is the log
http://paste.osmc.io/erumatayux

MY MISTAKE!!! VERY SORRY!!! I introduced wrong linceses!!!

very very sorry!!