Hey tedpr,
As per this discussion MicroStack Ussuri (242), can we disable TLS? - microstack - Charmhub, we cannot disable TLS.
So, what you have to do to solve this, is either add the CA-cert to your client (for example an ad-hoc fix for our use case would be to import the CA-cert to the JVM trust store).
A better way to solve this is to probably use a proxy to handle the TLS communication for your client, this is something known as SSL offloading or SSL termination.
To do so, you could for example set up an internal domain for your MicroStack instance, which points to your proxy (which contains the caCert for the MicroStack instance) and the forwards the connection using the proper certificate.
This information may be helpful to you Using SSL Certificates with HAProxy | Servers for Hackers