... and my lametric firmware is 2.3.3
I confirm (1 year later), that I still have the issue :)
I'm currently running on 2.2.2 but have again issues with HTTPS certificates
Please make sure you have updated your LaMetric firmware to 2.2.2 version. It contains a fix for the issue where some apps could not fetch any data due to the new Let's Encrypt's intermediate certificate.
There's been issues with HTTPS certificates recently - some important ones expired and a software update is required for the Lametric Time to fix it. Lametric support tell me that they're aware of the problem and are working on a fix.