private void authExternal() throws MessagingException { try { executeSimpleCommand(String.format("AUTH EXTERNAL %s", Base64.encode(mUsername)), false); } catch (Pop3ErrorResponse e) { /* * Provide notification to the user of a problem authenticating * using client certificates. We don't use an * AuthenticationFailedException because that would trigger a * "Username or password incorrect" notification in * AccountSetupCheckSettings. */ throw new CertificateValidationException( "POP3 client certificate authentication failed: " + e.getMessage(), e); } }