diff --git a/source/app/controllers/util.py b/source/app/controllers/util.py
index 097a546..859a409 100644
--- a/source/app/controllers/util.py
+++ b/source/app/controllers/util.py
@@ -1313,6 +1313,15 @@ def upload_file(rfc, opt, file_obj):
     return {'status': 'error', 'ok': False}
 
 
+def _get_pem_from_pfx(cert):
+    tmp_p12 = save_temp(cert.p12)
+    args = "openssl pkcs12 -in '{}' -clcerts -nodes -nocerts " \
+        "-passin pass:'{}' | openssl rsa".format(tmp_p12, _get_md5(cert.rfc))
+    result = _call(args)
+    _kill(tmp_p12)
+    return result.encode()
+
+
 def cancel_xml(auth, uuid, certificado):
     from .pac import Finkok as PAC
 
@@ -1328,7 +1337,7 @@ def cancel_xml(auth, uuid, certificado):
     data = {'ok': True, 'msg': msg, 'row': {'estatus': 'Cancelada'}}
     pac = PAC(auth)
     result = pac.cancel_xml(certificado.rfc, str(uuid).upper(),
-        certificado.cer_pem.encode(), certificado.key_enc.encode())
+        certificado.cer_pem.encode(), _get_pem_from_pfx(certificado))
     if result:
         codes = {None: '',
             'Could not get UUID Text': 'UUID no encontrado',
diff --git a/source/app/models/main.py b/source/app/models/main.py
index bbcdb9a..a03f6ff 100644
--- a/source/app/models/main.py
+++ b/source/app/models/main.py
@@ -2292,6 +2292,11 @@ class Facturas(BaseModel):
         auth = Emisor.get_auth()
         certificado = Certificado.select()[0]
         obj = Facturas.get(Facturas.id==id)
+
+        if obj.version == '3.2':
+            msg = 'No es posible cancelar CFDI 3.2'
+            return {'ok': False, 'msg': msg}
+
         data, result = util.cancel_xml(auth, obj.uuid, certificado)
         if data['ok']:
             obj.estatus = 'Cancelada'
diff --git a/source/app/settings.py b/source/app/settings.py
index df168c1..1c96b5f 100644
--- a/source/app/settings.py
+++ b/source/app/settings.py
@@ -117,4 +117,4 @@ IMPUESTOS = {
 DEFAULT_SAT_PRODUCTO = '01010101'
 DIR_FACTURAS = 'facturas'
 USAR_TOKEN = False
-CANCEL_SIGNATURE = True
\ No newline at end of file
+CANCEL_SIGNATURE = False
\ No newline at end of file