In LibreOffice, you can open and save documents that are stored on a WebDAV server, using the secure HTTPS protocol.
You must use the LibreOffice file dialogs to use WebDAV over HTTPS.
Choose LibreOffice - PreferencesTools - Options - . Ensure that Use LibreOffice dialogs is enabled. Click OK to close the dialog box.
Choose File - Open.
In the File name box, enter the path to the WebDAV folder. For example, enter https://192.168.1.1/webfolder to open a secure connection to the WebDAV server at the IP address 192.168.1.1, and to list the contents of the webfolder folder.
The first time you connect to a WebDAV server, you see the "Website Certified by an Unknown Authority" dialog.
You should click the Examine Certificate button and examine the certificate.
If you accept the certificate, choose "Accept this certificate temporarily for this session" and click OK. Now you can open and save files from the WebDAV server without further questions, until you exit LibreOffice.
If you do not trust the certificate, click Cancel.
If you did accept the certificate, you can now select the file name or file names you want to open and click Open.
If there is a mismatch of the domain name given in the certificate and the domain name you entered in the file dialog, then you see a dialog that allows you to choose from any of the following options:
View Certificate - Opens the View Certificate dialog.
Continue - If you are sure both domains are the same, click the Continue button.
Cancel Connection - Cancels the connection.
If you click Continue, you may see a dialog that asks you to enter your user name and password.