In a microservice infrastructure (does not fit the problem, I know ;)) you must not use:
server:
ssl:
trust-store: path-to-truststore...
trust-store-password: my-secret-password...
Instead the ribbon loadbalancer can be configuered:
ribbon:
TrustStore: keystore.jks
TrustStorePassword : example
ReadTimeout: 60000
IsSecure: true
MaxAutoRetries: 1
Here https://github.com/rajaramkushwaha/https-zuul-proxy-spring-boot-app you can find a working sample. There was also a github discussion about that, but I didn't find it anymore.