As documented in JBEAP-12279, remoting throws two different exceptions for failed authentication depending whether the connection was already opened or not: SaslException or AuthenticationException

But EJB clients use "instanceof SaslException" to determine, whether the fail was an authentication of or the target server is unavailable:

https://github.com/wildfly/jboss-ejb-client/blob/d2c6432b3a8357d18c2b65ace3080604e8feefa9/src/main/java/org/jboss/ejb/client/DiscoveryEJBClientInterceptor.java#L108

Should accept both exceptions, unless JBEAP-12279 will be resolved.
(but unification to AuthenticationException was rejected and reverted and unification to SaslException is blocked by elytron public api change - better to accept both exceptions here)