eM Client stopped connecting to my CardDAV server on my Synology NAS

Contacts
1

I’m using Synology Contacts on my Synology NAS.

I’ve added a CardDAV account in eM Client, so I can see and edit the contacts on my NAS in eM Client.

This worked great, until recently. Every year my Synology NAS gets (automatically) a new SSL certificate.

Side note: I’m using Synology Drive Client to make backups to my NAS. When my NAS gets a new SSL certificate, Synology Drive Client stops making backups to my NAS. I need to login again into my Synology NAS from Synology Drive Client, and then everything works fine again.

Now eM Client can not work with my Synology Contacts anymore. It shows the following error message (in the ‘Operations’ window, tab page ‘Log’):

“System.Security.Authentication.AuthenticationException: The remote certificate was rejected by the provided RemoteCertificateValidationCallback.”

How can I let eM Client connect to my NAS again, so my CardDAV account in eM Client is working again? (So I can update my contacts in eM Client, and eM Client can forward those changes to my NAS.)

2

Solved:

I went to my accounts list in eM Client, selected the CardDAV account, saved it in a local XML file on my hard disk, pressed the [save and close] button, confirmed that my CardDAV account was not showing up anymore in my ‘Contacts’ tab page in eM Client, and added my CardDAV account again. (I could find details like the CardDAV server in the saved XML file).

Then my contacts where downloaded in eM Client from my CardDAV server on my NAS again, and I could make edits in my contacts in eM Client, which synchronised automatically to the Contacts application on my NAS server.