diff --git a/source/finkok/finkok.py b/source/finkok/finkok.py
index 9e8f578..30e8938 100644
--- a/source/finkok/finkok.py
+++ b/source/finkok/finkok.py
@@ -43,6 +43,7 @@ logging.addLevelName(logging.INFO, '\x1b[32mINFO\033[1;0m')
 logging.basicConfig(level=logging.DEBUG, format=LOG_FORMAT, datefmt=LOG_DATE)
 log = logging.getLogger(__name__)
 logging.getLogger('requests').setLevel(logging.ERROR)
+logging.getLogger('zeep').setLevel(logging.ERROR)
 
 
 TIMEOUT = 10
@@ -94,6 +95,10 @@ class PACFinkok(object):
         self._transport = Transport(cache=SqliteCache(), timeout=TIMEOUT)
         self._plugins = [DebugPlugin()]
 
+    @property
+    def error(self):
+        return self._error
+
     def _validate_result(self, result):
         if hasattr(result, 'CodEstatus'):
             ce = result.CodEstatus
@@ -155,10 +160,10 @@ class PACFinkok(object):
         args = {
             'username': auth['user'],
             'password': auth['pass'],
-            'xml': cfdi,
+            'xml': cfdi.encode('utf-8'),
         }
         result = self._get_result(client, 'stamp', args)
-        if self.error:
+        if self._error:
             return ''
 
         data = {
diff --git a/source/tests/certificados/finkok.cer b/source/tests/certificados/finkok.cer
new file mode 100644
index 0000000..471d739
Binary files /dev/null and b/source/tests/certificados/finkok.cer differ
diff --git a/source/tests/certificados/finkok.enc b/source/tests/certificados/finkok.enc
new file mode 100644
index 0000000..b606c5f
--- /dev/null
+++ b/source/tests/certificados/finkok.enc
@@ -0,0 +1,30 @@
+-----BEGIN ENCRYPTED PRIVATE KEY-----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+-----END ENCRYPTED PRIVATE KEY-----
diff --git a/source/tests/certificados/finkok.key b/source/tests/certificados/finkok.key
new file mode 100644
index 0000000..0155f0a
Binary files /dev/null and b/source/tests/certificados/finkok.key differ