If a class contains a inner class which contains invalid proto annotations it will cause an error without specific information.
The same problem in the main class will show a valid message.

Valid if Message does not contain any Field(Index.YES)
ERROR [org.infinispan.server.hotrod.BaseRequestProcessor] ISPN005003: Exception reported org.infinispan.commons.CacheConfigurationException: ISPN028021: The configured indexed-entity type 'org.infinispan.reproducer.model.Message' must be indexed. Please annotate it with @Indexed and make sure at least one field has the @Field annotation, or remove it from the configuration.

Invalid Message for embedded class:
ERROR [org.infinispan.factories.ComponentRegistry] ISPN000538: Error stopping module org.infinispan.query.impl.LifecycleManager:reproducer org.hibernate.search.util.common.SearchException: HSEARCH000520: Hibernate Search encountered failures during bootstrap. Failures:

Infinispan Search Mapping:
type 'org.infinispan.reproducer.model.Message ([B)':
failures:

• null
  at org.hibernate.search.engine.reporting.spi.RootFailureCollector.checkNoFailure(RootFailureCollector.java:50)
  at org.hibernate.search.engine.common.impl.SearchIntegrationBuilderImpl.prepareBuild(SearchIntegrationBuilderImpl.java:253)
  at org.infinispan.search.mapper.mapping.SearchMappingBuilder.build(SearchMappingBuilder.java:135)
  at org.infinispan.query.remote.impl.LazySearchMapping.createMapping(LazySearchMapping.java:151)
  at org.infinispan.query.remote.impl.util.LazyRef.get(LazyRef.java:23)
  at org.infinispan.query.remote.impl.LazySearchMapping.mapping(LazySearchMapping.java:131)
  at org.infinispan.query.remote.impl.LazySearchMapping.close(LazySearchMapping.java:70)
  at org.infinispan.query.impl.LifecycleManager.cacheStopping(LifecycleManager.java:376)
  at org.infinispan.factories.ComponentRegistry.preStop(ComponentRegistry.java:253)
  at org.infinispan.factories.AbstractComponentRegistry.stop(AbstractComponentRegistry.java:305)
  at org.infinispan.cache.impl.CacheImpl.performImmediateShutdown(CacheImpl.java:1061)
  at org.infinispan.cache.impl.CacheImpl.stop(CacheImpl.java:1028)
  at org.infinispan.cache.impl.AbstractDelegatingCache.stop(AbstractDelegatingCache.java:521)
  at org.infinispan.cache.impl.AbstractDelegatingCache.stop(AbstractDelegatingCache.java:521)
  at org.infinispan.cache.impl.AbstractDelegatingCache.stop(AbstractDelegatingCache.java:521)
  at org.infinispan.manager.DefaultCacheManager.terminate(DefaultCacheManager.java:804)
  at org.infinispan.manager.DefaultCacheManager.stopCaches(DefaultCacheManager.java:897)
  at org.infinispan.manager.DefaultCacheManager.internalStop(DefaultCacheManager.java:873)
  at org.infinispan.manager.DefaultCacheManager.stop(DefaultCacheManager.java:848)
  at org.infinispan.server.SecurityActions.lambda$stopCacheManager$2(SecurityActions.java:78)
  at org.infinispan.security.Security.doPrivileged(Security.java:56)
  at org.infinispan.server.SecurityActions.doPrivileged(SecurityActions.java:40)
  at org.infinispan.server.SecurityActions.stopCacheManager(SecurityActions.java:84)
  at org.infinispan.server.Server.localShutdown(Server.java:560)
  at org.infinispan.server.Server.lambda$run$4(Server.java:472)
  at java.base/java.util.concurrent.CompletableFuture.uniWhenComplete(CompletableFuture.java:859)
  at java.base/java.util.concurrent.CompletableFuture$UniWhenComplete.tryFire(CompletableFuture.java:837)
  at java.base/java.util.concurrent.CompletableFuture.postComplete(CompletableFuture.java:506)
  at java.base/java.util.concurrent.CompletableFuture.complete(CompletableFuture.java:2073)
  at org.infinispan.server.DefaultExitHandler.exit(DefaultExitHandler.java:13)
  at org.infinispan.server.ShutdownHook.run(ShutdownHook.java:16)