FileLink fails with Thunderbird 68.4.1

I’m new to everything here (nextcloud, forum) and I hope I post in the right place.
Here is the issue I face with: when I try to link a file, although it’s uploaded in my nextcloud space, the link doesn’t appear into the message and a pop up says that the upload is impossible.
How can I fix it (if I can)?
I’m using ubuntu 18.04 and I create a webdav link without any problem.
Thank you in advance.

I use this and its ok for me :

I use it too :slight_smile:

Maybe you need to use an app password ?