Problems with webdav on NextCloud. Not all files open. Who faced?

Question

Windows

Good afternoon!
Colleagues, deployed NextCloud server 19.03 in the organization.
WebDav does not work normally. Some folders are not displayed via webdav, but are accessible via the web. Some are not available in both locations. After a while, the open folders are empty, you need to update the folder. When opening a pdf, it swears at the rights, although everything is right, the player does not open the video, etc.
Who faced, how did you decide?