Ardour export issue, only one channel [solved]

Hi, I’m pretty new on Ardour and I love it!
I have installed it on a DebIan buster and it work fine except for exporting to a file:

I have recorded my guitar by its own pickup to the left channel and a microphone to the right one.
During the mixing in Ardour both channel works great and in my headphone I can hear both sides but, when I export to a file it does only one channel and the other remain silent!

I tryed any connection on jack, even connect each track channel to both master channell! But it still export one side.

Any help? I don’t want to use Audacity again to convert my Ardour great mixing to a mono track :’(

similar issue on mixbus solved by going to Session->export (to audio files) >- channel tab
untick and retick master. Make sure the channel count is 2 on the same tab

It works! Thanks!!!

I have changed the title adding [solved]

P.S.

But is not a real fixing, Ardour deserv to be more reliable!
I hope developers can fix it soon, Good Work and thank You all for the good job!

I had this issue only once in an old session (I am on ardour/mixbus since 2016)…