[Users] Vcalendar plugin does not accept ssl certificate

[APM]

Dear all,

if I try to connect claws-email Vcalendar plubin with a redicale server
on a raspberry pi I received an error "SSL peer certificate or SSH
remote key was not OK".

My certificate is a self-signed certicate created with 'openssl' in
Debian Linux.

I read, that it is possible to deactivate the ssl-check.

The raspberry pi working only in a locale network with me as the only
user, but I prefer to use ssl.

Maybe you have a tipp for me?

Thank you!

Vcalendar Version: 3.17.8
Claws-email 3.17.8 from Debian bullseye repro


Piet