Electrum clients don't have a problem with self-signed certificates so no need to get a CA-signed one.

I attempted to connect to your node to debug the SSL problem and I think everything is okay except that you did not specify a Common Name for the certificate when you were creating it. You want to at least use icarus.tetradrachm.net as your common name (wildcards "*" will work just fine too) and create a new certificate. If you have the private key of the current certificate, you can attempt to create a new self-signed certificate using the same key but this time remembering to add a common name.

HTH