[Preacher]

Do you know which codec I missing and where I could find it?

Not me, as I don't have the file so can't interrogate it to determine what codecs it needs.

However, you can using a tool such as  https://www.videohelp.com/software/Codec-Tweak-Tool

[micanmg]

11:33:51.361 T:140517318363584 NOTICE: Starting Kodi (18.0-ALPHA2 Git:20180519-5afb532). Platform: Linux x86 64-bit
11:33:51.361 T:140517318363584 NOTICE: Using Release Kodi x64 build
11:33:51.361 T:140517318363584 NOTICE: Kodi compiled May 19 2018 by GCC 4.9.4 for Linux x86 64-bit version 3.13.11 (199947)
11:33:51.361 T:140517318363584 NOTICE: Running on Ubuntu 14.04.6 LTS, kernel: Linux x86 64-bit version 4.2.8

Well, it's all up to you guys, but if I were you, then I would stop supporting such outdated Kodi version. You are trying to support "Alpha 2" of Kodi 18 which is about over 2 years old now. I'm not going to support that, but I won't stop you

Beside the fact that the Ubuntu version he's running is outdated as well and I would also recommend to update that. Won't give any support for such a stone-aged OS as well.  

Sorry

Edit:

And for the record. As that file seems to be rar'd that's a good indicator that it was downloaded from somewhere. Not blaming that. Just saying that those downloaded rar-files which provide some ISO/img file might not be made to be run directly in Kodi then. Just wanted to say that this ISO might not play at all, no matter of the Kodi version. And we can't say what  might be wrong with it, because I suppose that the guys who is asking here didn't create the that file.

Just want to say that I have installed both Leia and matrix from qnapclub but they do not start at all, I have a thread for that too. It ends with them referring to qnapclub who do not respond at all. I have tried to both upgrade and downgrade the NAS, qts and hdstation but it does not help.

[Klojum]

Just want to say that I have installed both Leia and matrix from qnapclub but they do not start at all, I have a thread for that too. It ends with them referring to qnapclub who do not respond at all. I have tried to both upgrade and downgrade the NAS, qts and hdstation but it does not help.

Just my 2 cents... But a NAS should do what it is meant and designed to do, which is serving files and doing other server things. A media player is a totally different challenge, and if QNAP is unwilling or unable to provide 1st-line support for its products, then they shouldn't have started building half-baked mediaplayer solutions in the first place.

I'd suggest you get yourself a standalone Kodi solution, which depending on your 'use case' could be a simple Raspberry Pi set. Which is totally silent, uses only a couple of Watts, and with its CEC support can work OOTB with most TVs.