Problem solved! But I have no clue why…
cert-sync command multiple times, always with the same result:
....@....:~# sudo cert-sync /etc/ssl/certs/ca-certificates.crt Mono Certificate Store Sync - version 188.8.131.52 Populate Mono certificate store from a concatenated list of certificates. Copyright 2002, 2003 Motus Technologies. Copyright 2004-2008 Novell. BSD licensed. Importing into legacy system store: I already trust 176, your new list has 174 Import process completed. Importing into BTLS system store: I already trust 175, your new list has 174 Certificate added: C=IL, O=StartCom Ltd., OU=Secure Digital Certificate Signing, CN=StartCom Certification Authority 1 new root certificates were added to your trust store. Import process completed.
But I still got errors without using
--accept-any-ssl-certificate=true. Magically, it now works without this setting!