After Ubuntu Update websites with lets encrypt ssl marked as unsecure

After Ubuntu Update websites with lets encrypt ssl marked as unsecure. f.i. www.zukunftsforum-rissen.de

browse!

unsecure marker before the URL

secure sign

everytime

Ubuntu 19.10, Brave Version 0.70.123 Chromium: 78.0.3904.97 (Offizieller Build) (64-Bit)

Before updating Unbuntu from 19.4 the site was marked as secure