I had to create a SAN cert. If you google you will find a lot of articles telling you to modify your openssl.cfg . You can also do it with a command. I put some special characters in the command because they need to be escaped. You can see below how:
req -newkey rsa:2048 -keyout new_private.key -sha256 -subj "/C=NL/ST=Noord-Holland/L=\'s\-Hertogenbosch/O=Your Organization/OU=I\&CT/CN=common_name.nl/subjectAltName=DNS.1=alternate_name" -out new_certificate_request.csr
You can specify more alternate names by adding more entries:
DNS.2=alternatename2
DNS.3=alternatename3
etc