O365: authenticator fix regression

git-svn-id: https://svn.code.sf.net/p/davmail/code/trunk@3721 3d1905a2-6b24-0410-a738-b14d5a86fcbd

Author: mguessan

src/java/davmail/exchange/auth/O365Authenticator.java

@@ -291,7 +291,7 @@ public void authenticate() throws IOException {
     }
 
     private void checkConfigErrors(JSONObject config) throws DavMailAuthenticationException {
-        if (config.optString("strServiceExceptionMessage") != null) {
+        if (config.optString("strServiceExceptionMessage", null) != null) {
             throw new DavMailAuthenticationException("EXCEPTION_AUTHENTICATION_FAILED_REASON", config.optString("strServiceExceptionMessage"));
         }
     }