diff --git a/gajim/common/connection.py b/gajim/common/connection.py
index 5884ce9a0..c8afae4b3 100644
--- a/gajim/common/connection.py
+++ b/gajim/common/connection.py
@@ -33,6 +33,7 @@
 ##
 
 import os
+import sys
 import random
 import socket
 import operator
@@ -49,7 +50,7 @@ from string import Template
 from urllib.request import urlopen
 from urllib.error import URLError
 
-if os.name == 'nt':
+if sys.platform in ('win32', 'darwin'):
     import certifi
 import OpenSSL.crypto
 import nbxmpp
@@ -1175,7 +1176,7 @@ class Connection(CommonConnection, ConnectionHandlers):
         port = self._current_host['port']
 
         cacerts = ''
-        if os.name == 'nt':
+        if sys.platform in ('win32', 'darwin'):
             cacerts = certifi.where()
         mycerts = common.configpaths.get('MY_CACERTS')
         tls_version = app.config.get_per('accounts', self.name, 'tls_version')
@@ -1374,7 +1375,7 @@ class Connection(CommonConnection, ConnectionHandlers):
             url = 'https://%s/.well-known/posh/xmpp-client.json' % hostname
 
         cafile = None
-        if os.name == 'nt':
+        if sys.platform in ('win32', 'darwin'):
             cafile = certifi.where()
 
         log.info('Request POSH from %s', url)
diff --git a/gajim/common/httpupload.py b/gajim/common/httpupload.py
index 6ca95d7a2..369fb0d91 100644
--- a/gajim/common/httpupload.py
+++ b/gajim/common/httpupload.py
@@ -15,6 +15,7 @@
 # along with Gajim.  If not, see <http://www.gnu.org/licenses/>.
 
 import os
+import sys
 import threading
 import ssl
 import urllib
@@ -35,7 +36,7 @@ from gajim.common.connection_handlers_events import HTTPUploadProgressEvent
 from gajim.common.connection_handlers_events import MessageOutgoingEvent
 from gajim.common.connection_handlers_events import GcMessageOutgoingEvent
 
-if os.name == 'nt':
+if sys.platform in ('win32', 'darwin'):
     import certifi
 
 log = logging.getLogger('gajim.c.httpupload')
@@ -300,7 +301,7 @@ class ConnectionHTTPUpload:
                 log.warning('CERT Verification disabled')
                 transfer = urlopen(request, timeout=30, context=context)
             else:
-                if os.name == 'nt':
+                if sys.platform in ('win32', 'darwin'):
                     transfer = urlopen(
                         request, cafile=certifi.where(), timeout=30)
                 else: