The phone supports the establishment of secure data connections on the Internet with the TLS security protocol (Transport Layer Security). With TLS, the client (the phone) uses certificates to identify the server. These certificates must be stored on the base station.
You can manage them via this Web page Settings – Telephony - Security.
The lists contain the server or CA certificates (certificates from certification points) that have already been implemented by default or have been downloaded via the Web configurator and are classed as valid, i.e., have been accepted.
Deleting a certificate from one of the lists: Select the certificate and click on the [Remove] button. The certificate is deleted from the list immediately.
Checking information about a certificate: Select the certificate and click on the [Details] button. A new Web page appears, displaying the properties of the certificate. If one of the certificates becomes invalid, e.g., because it has expired, it is transferred to the Invalid Certificates list.
You can import new certificates as follow:
The list of invalid certificates contains the certificates received from servers that have not passed the certificate check, and certificates from the Server Certificates / CA Certificates lists that have become invalid. You have the following options: