To download the dependency, maven will need a version tag. This would be the most recent version:

<dependency>
    <groupId>com.playtika.reactivefeign</groupId>
    <artifactId>feign-reactor-spring-cloud-starter</artifactId>
    <version>4.2.1</version>
</dependency>

As mentioned by @rzwitzerloot, if you wanted to deal with the cause of the issue, you'd have to rewrite this in a reactive way, passing in success and failure callbacks to the token validation.

That may be a nontrivial rewrite, so you might want to first establish whether thread starvation is a relevant issue in your specific setup.

If you prefer the blocking style, you might get similar performance and eliminate starvation by using virtual threads.