I had a Synology 918+ working properly over WebDAV using NetDrive3. I changed home and now everything works except for NetDrive3.
I opened the new router to forward WebDAV ports to the server as I had it before, and every external access to the server works fine, except for NetDrive3.
It always shows the following error: “LOGIN FAILED. PLEASE CHECK LOGIN CREDENTIALS” (my username and password are correct).
This issue was finally solved and I don’t have the slightest idea on how was it solved. After several talks with my ISP technical service, Synology forums and Netdrive, yesterday it finally started working again.
If I have to guess, I think the problem was probably an issue on the Synology NAS configuration. For some reason the WebDAV application wasn’t working properly. Several restarting of the NAS later, it works.