WebDAV and Mac Finder failed login
I have a Synology NAS DS415+ and multiple Macbooks and have been struggling with a WebDAV login problem. It wasn't an issue until recently because I could access files on the NAS via Mac Safari browser but now I want to use WebDAV to mount the NAS volume in Finder. I've read many Apple and Synology forum posts from users with similar struggles to mine but I still can't figure out what I'm doing wrong. Here's some info:
I can login into WebDAV both locally and remote using Cyberduck, CalDAV and Synology DSfile (on iPhone). This means router and WebDAv port forwarding is correct. It also means user permissions and password are correct. However I cannot login either local or remote using Cmnd+K "Connect to Server". I get the usual Finder server login dialog box so I presume this means I am reaching the NAS but when I enter username and password I get an error message "There was a problem connecting to the server. Check the server name or IP address". If I deliberately enter a wrong password it simply returns to the login screen. WebDAV log shows CalDAV and DSfile logins but no reports of failed logins via Cmnd+K. I've run out of ideas and would really appreciate help.
mbp, Mac OS X (10.5.2)