How do I create certificates for the Blynk library?

In the certificates folder, I need to update the certificates - How to create and save them from the browser?
Path to folder … \ Blynk \ src \ certs
Its content:

I am looking at the certificate in a browser. Also I can save it. but there are many different options.

While the certificate is invalid I get the error:

BSSL:_connectSSL: start connection
BSSL:_wait_for_handshake: failed
BSSL:Couldn't connect. Error = 'Chain could not be linked to a trust anchor.' [132583] NTP time: Sat Dec  4 09:55:16 2021

Is this Legacy local server?

If so, have you followed the instructions…


I mean these certificates:

Okay, I no longer run a Legacy local server, and I’ve never used SSL when I did, so the answer will need to come from someone else I’m afraid.


I’ll try to figure it out and post the answer here.