Problem with Desktop Audio

[nassim.gh]

I have recorded several screens with OBS and had no problem so far. Recently, I have recorded a very important meeting that lasts for 1 hour and 15 minutes. Now I checked the video and realized the sound of the person in the meeting has not been recorded. I had three more similar meetings after that for which I used OBS as well without changing the configuration and settings in OBS or my laptop. I am surprised to see their voice has been recorded but the first video has a problem with desktop audio. I am using a VLC media player to play all videos and during all the meetings I used the same headsets and the audio device in OBS is on the default.
I am wondering why the first meeting encountered a problem with desktop audio recording. Is there any way to fix this?

 

[WBE]

without changing the configuration and settings in OBS or my laptop.

Unless you believe in magic, there must be something different... Based on this information it's hard or impossible to tell what factor actually is causing this error. Could you please upload the log files of those four OBS sessions? That might not even lead to a conclusive answer, but it's worth the try.

Log files can be found at %APPDATA%\obs-studio\logs
Their filenames contain the date/time of the start of the OBS Studio session.