For some reason, I don’t understand how to connect to Fastmail remote files via WebDav via Dolphin (23.08.5). I tried to follow this Remote file access – Fastmail but no luck at all.
And when I try to use the add Network Folder Wizard (as shown below)), I don’t know what to enter in for port or folder.
Webdav are extensions to http, so they use port 80 and 443. As it’s Fastmail it’s most likely 443, you may need to create a separate app password for WebDav (been a while since I used Fastmail so can’t remember exactly, but I know you needed a separate app password for phones and email clients). So the details for the wizard should be something like
Name: Fastmail WebDav (or whatever you want to name it)
Server: https://webdav.fastmail.com
Port: 443 (since the address is https).
Folder: Leave blank, it should automatically take you to your files when you login.
Username & Password: You will need to generate an app password in Fastmail that allows Files access. Which is no different than generating an app password for 3rd party clients, et cetera.
Your {My Files} directory will be located in /username.your.domain/files/. Alternatively, use the hostname https://myfiles.fastmail.com/ to be rooted in your {My Files} directory.