Note the owner of a SRV record is a service name not a host name. There are a few reasons for this oddity: partly so it matches with DANE for MX records, partl

Note the owner of a SRV record is a service name not a host name. There are a few reasons for this oddity: partly so it matches with DANE for MX records, partly to support large scale virtual hosting without reissuing certificates. You should be able get a cert with subject names covering the server host name(s) and the service name(s).