Client certificate in blynk Python for local server

Hello guys!
I am using the following code to securely connect to the my server blynk.

blynk = blynklib.Blynk(BLYNK_AUTH, server='myhost',ssl_cert=CERT, port=9443,

fullchain file matches the certificate file on the server:

server.ssl.cert = /etc/letsencrypt/live/mydomain/fullchain.pem

Also I am using a other port in


I get an error:

2021-07-21 16:36:54,216 [INFO]  Using SSL socket...
2021-07-21 16:36:55,003 [INFO]  [ERROR]: Connection with the Blynk server failed: [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed: unable to get issuer certificate (_ssl.c:1056)
Connection closed

Code from example to connect to blynk-cloud:

blynk = blynklib.Blynk(BLYNK_AUTH, port=443, ssl_cert='../certificate/',

Log of my blynk server:

14:54:23.740 INFO - Reports : 0
14:54:23.741 INFO - Didn't find Let's Encrypt certificates.
14:54:23.741 INFO - Automatic certificate generation is turned ON.
14:54:23.742 INFO - Using native openSSL provider.
14:54:24.526 INFO - HTTP API and WebSockets server listening at **** port.
14:54:24.528 INFO - HTTPS API, WebSockets and Admin page server listening at 9443 port.
14:54:24.528 INFO - Mqtt hardware server listening at 8440 port

But in response to the request, I get:


Let’s encryption error nope affects this. So wrote the @mstoj in the github :

Important: Make sure that the name to the server file is correct!
Although you will receive ‘INFO’ notices stating ‘Didn't find Let's Encrypt certificates’ and ‘Automatic certificate generation is turned ON’, the certificates will have been installed correctly as there are no ‘WARN’ notices.