How to skip TLS handshake verfication for a service

im using nomad with consul connect and API gateway
im trying to add kasm service. which is accessed via https.
when i try to access it from the browser i keep getting:

upstream connect error or disconnect/reset before headers. reset reason: connection termination

is there a way to configure sidecar proxy to access it via https?
is it possible to configure sidecar proxy to skip TLS handshake verification? and how?
is it possible to configure sidecar proxy to present custom certificates?
thanks