Currently, for any error in doTestConnection, the code in catch, RocketChatNotifier.java, l599.
However, in this catch, the following condition is incorrect.
if (e.getCause() != null &&
e.getCause().getClass() == SSLHandshakeException.class || e.getCause().getClass() == ValidatorException.class)
Indeed, the third part of this, is not protect by the first part. In other terms, we can have an NPE when e.getCause() returns null because the condition "e.getCause().getClass() == ValidatorException.class" is eval.