Technogym app (NL) stopped working correctly

I have to use the Technogym app to make workout appointments. Worked perfectly untill October 2024. Since then:

  • app can be used only once. I shut down my smartphone most of the time.
  • after a restart of smartphone, the app only shows the opening screen.
  • to get it working, I have to deinstall the app, install it again, click several times on all sort of messages and settings (which I do not want) to make the appointment.
  • If I deinstall, reinstall but not open the app, and restart the smartphone, the T app also shows only the opening screen.
    I have been in contact with Technogym, they say that they investigate, but nothing happens.
    The Technogyn app is the only app which shows these problems, all others, like Whatapp, Albert Heyn, La Place etc etc. work fine !
    I also contacted Fairphone support, but no response yet.
    Fairphone 3, up to date
    Android 13

Any other Dutch people with the same problem?