Hello from France, Vegas Community ! 🇫🇷

My problem: I'm trying to render a Vegas Pro 16/9 video project in Sony AVC / MVC format, but in a vertical format (720x1280, 30ips OR 1080x1920, 30ips), to fit the story standards on Facebook, Instagram...
It always worked good when i change the proprieties of the project + personalize the parameters of the rendering.

BUT...

Since I updated to V17, (with old Vegas 16 app keeped), it starts to bug:
When i try to render, i always have the error message :

"Vegas Pro 17 an error occurred while creating the multimedia file. Invalid argument was specified"
"Vegas Pro 17 une erreur s'est produite lors de la création du fichier multimedia. Un argument non valide a été spécifié", in french

WHAT I ALREADY TRY :

• Disable GPU rendering.
• delete all Render Templates and favourites in C:\Users\%USERNAME%\AppData\Roaming\VEGAS\Render Templates
• uninstall V16 + V17, reboot, install just V17, reboot.
• Change the render format to MAGIX AVC MP4 (works, BUT this format video is really slow to render and can't be previewed/played in Facebook, Twitter & Instagram phone App !)
• Change the parameters of Sony AVC / MVC format (I try almost everything !)
• Restart a project clean, without an old session.

...and still have the same error message!

Sony AVC / MVC format details :

Utilisez ce paramètre pour créer un fichier 16:9 de qualité maximum téléchargeable sur des sites Internet.
Audio : 128 Kbits/s; 48 000 Hz; 16 Bit; Stéréo; AAC
Vidéo : 30 ips; 720 x 1280 Progressif; YUV; 16 Mbits/s
Forme du pixel : 1,000

FUNNY THING...

When I try to render in a common resolution (classical 720/1080) : It works !
When i try to render in a square format (720 x 720) : it works !
When i try to render in a strange resolution, (not a 9/16, like a 720 x ....1200 or 1290) : It works !
When i try to render in a bigger vertical video format like 1080 x 1920 : It does not works !
When i change the parameters of the render mode, when I change "1280 x 720" to "720 x 1280", when I save this render model, 1280 is automaticly swipped to 1080 !!!

I do not understand what I'm doing wrong in my rendering procedure, when it worked well before ...

Any idea ?

Thanks a lot for your precious help !