Adding certificate to Chromium WR21

[Hemingway]

How to add certificates and open https page on Chromium Android WR21 without information about your connection is not private?

[webiq-sk]

Just a general answer from me: the message relates to the name in the certificate not matching the hostname the certificate is used on, e.g. if you have a TLS certificate for subdomain.example.com and also use it on othersubdomain.example.com or you're accessing the IP address, but it's not included in the certificate.
See also https://stackoverflow.com/a/68351111 

[Hemingway]

Sorry, it was an incorrect pic. The correct one is:

But I don't understand where at Chromium I can add certificates. 

[webiq-sk]

This shows that the browser received your certificate, obviously. However, your certificate is not signed by a trusted root certification authority (CA), therefore you have to add the CA's public certificate to the trusted root certificate store of the Android device.
If you don't know the concept of CAs see here: https://opensource.com/article/19/11/internet-security-tls-ssl-certificate-authority 

I can't help you with BR panels, but in general this should show you how to do that on a normal Android device (like a phone):
https://www.google.com/search?q=android+installing+a+root+CA+certificate

[CodeShepherd]

There is also the how to "How to make an HTTPS connection with ctrlX OS Web Server" in this community available, explaining how to create certificates.