I don't know if it is due to a certificate but I can confirm that the ausweisapp2 stopped working for me around April this year. My smartphone can't be used as card reader any more. It is shown as "gekoppelt, aber nicht verfügbar" and "Verfügbar - Klicken zum Koppeln" at the same time. Starting "Koppeln" anew doesn't change anything. Kubuntu 20.04, ausweisapp2 1.20.0-1build1
I don't know if it is due to a certificate but I can confirm that the ausweisapp2 stopped working for me around April this year. My smartphone can't be used as card reader any more. It is shown as "gekoppelt, aber nicht verfügbar" and "Verfügbar - Klicken zum Koppeln" at the same time. Starting "Koppeln" anew doesn't change anything. Kubuntu 20.04, ausweisapp2 1.20.0-1build1