Timeout error

[HajarMed]

i try to connect to the opcexpert server using the following code:

from opcua import Client

server_URL = "opc.tcp://localhost:57888/OpcExpert"
path_client_cert = "C:/Program Files/OPC Expert/Expert Resources/CertificateStores/UA Applications/certs/certificate.der"
path_private_key="C:/Program Files/OPC Expert/Expert Resources/CertificateStores/UA Applications/certs/rsa_private.pem"
path_server_cert="C:/Program Files/OPC Expert/Expert Resources/CertificateStores/UA Applications/certs/server_cert.der"
client = Client(server_URL)
client.set_security_string("Basic256Sha256,SignAndEncrypt," + path_client_cert +"," + path_private_key + "," + path_server_cert + "")
client.application_uri = ""
client.secure_channel_timeout = 10000
client.session_timeout = 10000
client.connect()

i get this error:
Exception has occurred: TimeoutError
exception: no description
File "C:\Program Files\OPC Expert\Expert Resources\CertificateStores\UA Applications\certs\opcexpert_security", line 16, in
client.connect()
TimeoutError:

Any help?