I have changed the Engine SSL certificate with our own certificates (using FreeIPA), i have followed the procedure described in the documents carefully and it is indeed working well. I haven now tried to upload an ISO and it fails, using "test connection" says the connection to the imageio service is ok, but when the upload starts it fails. I can see those errors in the ovirt-imageio daemon log file. 2020-07-10 06:00:48,386 ERROR (Thread-11) [http] Server error Traceback (most recent call last): File "/usr/lib64/python3.6/site-packages/ovirt_imageio/_internal/http.py", line 699, in __call__ self.dispatch(req, resp) File "/usr/lib64/python3.6/site-packages/ovirt_imageio/_internal/http.py", line 744, in dispatch return method(req, resp, *match.groups()) File "/usr/lib64/python3.6/site-packages/ovirt_imageio/_internal/cors.py", line 84, in wrapper return func(self, req, resp, *args) File "/usr/lib64/python3.6/site-packages/ovirt_imageio/_internal/images.py", line 66, in put backends.get(req, ticket, self.config), File "/usr/lib64/python3.6/site-packages/ovirt_imageio/_internal/backends/__init__.py", line 53, in get cafile=config.tls.ca_file) File "/usr/lib64/python3.6/site-packages/ovirt_imageio/_internal/backends/http.py", line 48, in open secure=options.get("secure", True)) File "/usr/lib64/python3.6/site-packages/ovirt_imageio/_internal/backends/http.py", line 63, in __init__ options = self._options() File "/usr/lib64/python3.6/site-packages/ovirt_imageio/_internal/backends/http.py", line 364, in _options self._con.request("OPTIONS", self.url.path) File "/usr/lib64/python3.6/http/client.py", line 1254, in request self._send_request(method, url, body, headers, encode_chunked) File "/usr/lib64/python3.6/http/client.py", line 1300, in _send_request self.endheaders(body, encode_chunked=encode_chunked) File "/usr/lib64/python3.6/http/client.py", line 1249, in endheaders self._send_output(message_body, encode_chunked=encode_chunked) File "/usr/lib64/python3.6/http/client.py", line 1036, in _send_output self.send(msg) File "/usr/lib64/python3.6/http/client.py", line 974, in send self.connect() File "/usr/lib64/python3.6/http/client.py", line 1422, in connect server_hostname=server_hostname) File "/usr/lib64/python3.6/ssl.py", line 365, in wrap_socket _context=self, _session=session) File "/usr/lib64/python3.6/ssl.py", line 776, in __init__ self.do_handshake() File "/usr/lib64/python3.6/ssl.py", line 1036, in do_handshake self._sslobj.do_handshake() File "/usr/lib64/python3.6/ssl.py", line 648, in do_handshake self._sslobj.do_handshake() ssl.SSLError: [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed (_ssl.c:897) Looking at old posts here, i have also tried: keytool -importcert -trustcacerts -keystore /etc/pki/ovirt-engine/.truststore -storepass mypass -file /etc/pki/ovirt-engine/apache-ca.pem And restarted both the ovirt-imageio service and the ovirt-engine service, it didn't help.