Impossible to share external storage folder with other users

I come here to know if I am alone about my problem …
My nextcloud server works fine but I have a problem just in a specific case.
I can share a folder with other user on web interface on my computer in any case (including in my external storage).
In Android application, I can share folder with other users just in basic tree.
If i try to share a folder in my external storage, I have an android toast message
"an error occurred while attempting to share this file or directory"
I try to analyse owncloud and apache log but no error message. I try to analyse android logcat but nothing too.
Someone can try with his server and android app please ?

I have always the same problem but the message is more explicite : no server instance found
noboby have this problem please ?

Hi again !
After few major et minor update, no amelioration …
Am I alone with this problem ?
Nobody can help me to find why that don’t work ?

please, anyone can help me ?
I have always the same problem… :disappointed_relieved: