Hi Tflidd
Thank you very much for your reply
I checked login-flow documentation chapter ‘Login flow v2’
https://docs.nextcloud.com/server/latest/developer_manual/client_apis/LoginFlow/index.html#login-flow-v2
That is all about https.
And in the German installation guide I used one year ago ( https://www.heise.de/ratgeber/Nextcloud-als-Docker-Instanz-im-NAS-einrichten-4199681.html ) I found this:
“Mit einem ReverseProxy-Eintrag im NAS leitet nginx HTTPS Verbindungswünsche an den Nextcloud Container weiter, der selbst nur HTTP spricht”
(“With a reverse proxy entry in the NAS, nginx forwards HTTPS connection requests to the NextCloud container, which itself only speaks HTTP”)
Probably this reverse proxy is misconfigured not the wizard.