The server is not available at all. I tried straight from the documentation. [image] Writing your own check plug-ins Here you will learn how to develop Checkmk plug-ins — with everything that goes with it, especially with the new Check API developed in version 2.0.0. …

Works for me. Your screenshot shows some details: ERR_HTTP2_INADEQUATE_TRANSPORT_SECURITY. Perhaps some transparent firewall/proxy in between?

The server is not available

martin.schwarz (Martin Schwarz) February 10, 2022, 5:30pm 3

Or perhaps your browser (cert store) is lacking the ISRG Root X1 from Let’s Encrypt?

Can you connect to other sites using LE certs?