Trace id is not Propagating to called service

[RoopaRJ]

when i am calling another microservice using resttemplate it is working fine but when i tried with httpclient/webclient trace id is not propagating to the next service.
example: in logs for service a it is showing traceid1, in service b it is showing traceid2 ideally we should get same trace id's in for the entire journey of a single request

below are the dependencies used in my springboot3 application for distributed tracing:
implementation platform('io.micrometer:micrometer-tracing-bom:latest.release')
implementation 'io.micrometer:micrometer-tracing-bridge-brave'
implementation 'io.zipkin.reporter2:zipkin-reporter-brave'
implementation 'io.zipkin.reporter2:zipkin-sender-urlconnection'
implementation("org.springframework.boot:spring-boot-starter-webflux:3.0.5")

in application.yml i have added:
zipkin:
tracing:
endpoint: http://localhost:9411/api/v2/spans

i am autowiring the Tracer to create spans like below:
tracer.spanBuilder().name("randomSpan").start()

this is how i am calling another service using webclient:
webClient.post()
.uri(URI.create("url"))
.contentType(MediaType.APPLICATION_JSON)
.header("X-B3-TraceId", tracer.currentTraceContext().context().traceId())
.body(BodyInserters.fromValue(body))
.retrieve()
.bodyToMono(java class)
.block()