Joplin and Synology WebDAV cert error because of previous duckdns one

I hope everyone is doing well. I am switching from OneNote to Joplin. I am trying to setup sync to my homelab's NAS. I have enabled WebDAV. I also configured DDNS to NEW URL for access and then got a certificate from Let's Encrypt. When I test the connection it fails and tells me that the new name isn't an altname for the certificate and it then lists the cert I have for HomeAssistant from duckdns.
The message states:
"request to NEW URL failed. Reason hostname/ip does not match certificate's altnames. Host NEW URL is not in the cert's altnames. DUCKDNS NAME (code ERR_TLS_CERT_ALTNAME_INVALID)"

any guidance would be appreciated. I have been searching a few hours and can't seem to find any useful information that doesn't include breaking my working HomeAssistant configuration.

thank you!

1 Like

Hello and welcome,

your WebDav URL (Host part) musst match on of the certificate names. It sounds you use a name or IP witch is not par of the altnames of the certificate list.
What do you use as WebDav URL?
You can check your certificate response from your Synology with: openssl s_client -showcerts -servername <NAME> -connect <NAME>:<PORT>, when you post the output I can check it.

I was able to get it solved. Synology - under security/certificate/settings has a list of the services and the associated certificate it uses. WebDAV defaulted to use the host's synology*.com certificate. I changed it to use the one I created for the DDNS url I made for this functionality and it now works. I am now able to sync to my NAS over https. I disabled port 5005 (http) in the WebDAV configuration in the Synology so that only https can be used.
thank you for the help!

This topic was automatically closed 30 days after the last reply. New replies are no longer allowed.