diff --git a/afip_auth.py b/afip_auth.py
index a1b0ca2..80fbe61 100644
--- a/afip_auth.py
+++ b/afip_auth.py
@@ -60,7 +60,7 @@ def authenticate(service, certificate, private_key, force=False,
             # cryptographically sing the access ticket
             cms = wsaa.SignTRA(tra, certificate, private_key)
             # connect to the webservice:
-            wsaa.Conectar(cache, wsdl, proxy)
+            wsaa.Conectar(cache, wsdl, proxy, cacert=True)
             # call the remote method
             ta = wsaa.LoginCMS(cms)
             if not ta:
@@ -79,7 +79,7 @@ def authenticate(service, certificate, private_key, force=False,
             # cryptographically sing the access ticket
             cms = wsaa.SignTRA(tra, certificate, private_key)
             # connect to the webservice:
-            wsaa.Conectar(cache, wsdl, proxy)
+            wsaa.Conectar(cache, wsdl, proxy, cacert=True)
             # call the remote method
             ta = wsaa.LoginCMS(cms)
             if not ta:
diff --git a/currency.py b/currency.py
index d9c1778..d67ae21 100644
--- a/currency.py
+++ b/currency.py
@@ -88,7 +88,7 @@ def get_afip_rate(self, service='wsfex'):
         cache_dir = afip_auth.get_cache_dir()
         ws.LanzarExcepciones = True
         try:
-            ws.Conectar(wsdl=wsdl, cache=cache_dir)
+            ws.Conectar(wsdl=wsdl, cache=cache_dir, cacert=True)
         except Exception as e:
             msg = ws.Excepcion + ' ' + str(e)
             logger.error('WSAA connecting to afip: %s' % msg)
diff --git a/invoice.py b/invoice.py
index ca89d4f..82d7808 100644
--- a/invoice.py
+++ b/invoice.py
@@ -1200,7 +1200,7 @@ def conect_afip(cls, ws, wsdl, vat_number, auth_data):
         cache_dir = afip_auth.get_cache_dir()
         ws.LanzarExcepciones = True
         try:
-            ws.Conectar(wsdl=wsdl, cache=cache_dir)
+            ws.Conectar(wsdl=wsdl, cache=cache_dir, cacert=True)
         except Exception as e:
             msg = ws.Excepcion + ' ' + str(e)
             logger.error('WSAA connecting to afip: %s' % msg)
diff --git a/setup.py b/setup.py
index 33d7922..b21fda6 100644
--- a/setup.py
+++ b/setup.py
@@ -55,6 +55,7 @@ def get_require_version(name):
 requires.append('httplib2')
 requires.append('pyafipws')
 requires.append('pysimplesoap')
+requires.append('certifi>=2020.4.5.1')
 #requires.append('suds>=0.4')
 
 tests_require = [get_require_version('proteus'), 'pytz']
diff --git a/tests/scenario_invoice_pos_electronic.rst b/tests/scenario_invoice_pos_electronic.rst
index dae2372..05f50e5 100644
--- a/tests/scenario_invoice_pos_electronic.rst
+++ b/tests/scenario_invoice_pos_electronic.rst
@@ -179,7 +179,7 @@ SetUp webservice AFIP::
     >>> wsfev1.Cuit = company.party.vat_number
     >>> wsfev1.Token = auth_data['token']
     >>> wsfev1.Sign = auth_data['sign']
-    >>> wsfev1.Conectar(wsdl=URL_WSFEv1, cache=cache)
+    >>> wsfev1.Conectar(wsdl=URL_WSFEv1, cache=cache, cacert=True)
     True
 
 Get CompUltimoAutorizado and configure sequences::
diff --git a/tests/scenario_invoice_pos_electronic_fce.rst b/tests/scenario_invoice_pos_electronic_fce.rst
index 53c708f..1a26480 100644
--- a/tests/scenario_invoice_pos_electronic_fce.rst
+++ b/tests/scenario_invoice_pos_electronic_fce.rst
@@ -216,7 +216,7 @@ SetUp webservice AFIP::
     >>> wsfev1.Cuit = company.party.vat_number
     >>> wsfev1.Token = auth_data['token']
     >>> wsfev1.Sign = auth_data['sign']
-    >>> wsfev1.Conectar(wsdl=URL_WSFEv1, cache=cache)
+    >>> wsfev1.Conectar(wsdl=URL_WSFEv1, cache=cache, cacert=True)
     True
 
 Get CompUltimoAutorizado and configure sequences::
diff --git a/tests/scenario_invoice_pos_electronic_wsfex.rst b/tests/scenario_invoice_pos_electronic_wsfex.rst
index 0a2db96..cf1fe81 100644
--- a/tests/scenario_invoice_pos_electronic_wsfex.rst
+++ b/tests/scenario_invoice_pos_electronic_wsfex.rst
@@ -191,7 +191,7 @@ SetUp webservice AFIP::
     >>> wsfexv1.Cuit = company.party.vat_number
     >>> wsfexv1.Token = auth_data['token']
     >>> wsfexv1.Sign = auth_data['sign']
-    >>> wsfexv1.Conectar(wsdl=URL_WSFEXv1, cache=cache)
+    >>> wsfexv1.Conectar(wsdl=URL_WSFEXv1, cache=cache, cacert=True)
     True
 
 GetLastCMP and configure sequences::