Service Principle and Gateway Access/Permissions

We are attempting to automate some processes in our environment and we need to modify datasets to point to new backend servers.

We can successfully use the service principle to use APIs and change the parameter of the dataset to a new server, but we can’t bind that new server to the appropriate gateway because the service principle cant be added to the gateway. We’ve also tried assigning the service principle application to a security group, but security groups without mail enabled also can’t be added to the gateway. And we can’t add applications to a security group with mail enabled.

Does anyone know how to grant a service principle access to gateways?