Hello,
I have a problem with the connection of WebDAV.
I have set up sync via WebDAV on my NAS.
But when I enter the connection via https:// and also select the correct port from my NAS for it I always get a connection problem (see screenshot):
I have now changed it first to http://
The problem exists from any terminal device. No matter if desktop or iPhone or iPad.
Can anyone help me why this is so, or what I can change here so that it works again via https://.
Thanks a lot
Can you connect via http and https in Finder?
Did you forget to add the port to the URL? If your NAS is a Synology and haven’t changed the default ports, URL should something like:
http://ddnsname.synology.me:5005/Path
or
https://ddnsname.synology.me:5006/Path
where “ddnsname” is they name you connect to your Synology from outside:https://ddnsname.quickconnect.to
Apart, you must set read and write permissions to the shared folder for the user you are connecting to. And open your router to redirect 5005 or 5006 to your NAS IP.
-1004 means cannot connect to host.
Or “ddnsname” is your local IP or hostname if only syncing on your network. 
Same problem here. Started about 2-3 weeks ago.
On DTTG iPhone and iPad, the “.manifest” is missed. Then on DT3, when I try to select “check thoroughly/…gründlich überprüfen” storage location with OPT-right mouse button, I get the error message below after a few seconds.
My NAS ist QNAP with Firmware 5.0.1 Build 20230112
iPhone DTTG Version 3.6.4(17291)
The inability to connect to the host is a server or network issue, not a sync issue.
Are you trying to access the QNAP from outside your network?
Form outside as well as from inside.
As @BLUEFROG said: this is a network issue, probably not related to SSL. You should go through the usual network debugging steps:
