I was able to find and add the "ADAC" charging card in the app, but after a few seconds it always disappeared on its own.
However, it was possible to enter the card on the website. Then it also appeared in the app and has remained there so far.
Could you tell me in which version of the app this happens? iOS, Android or Android Automotive?
I can't say the exact version. But of course I installed the latest version from the Play Store that day before writing the post. I wanted to make sure it was happening with the latest version.
The problem was with the OnePlus8T with the latest Android 11 there. I then use the phone with Android Auto in a Peugeot e208. But the entry of the charging card has disappeared from the app without the car being connected. I made the entry and then it only took less than 1 minute for the disappeared again.
When I entered the charging card on the website, it also took less than 1 minute until the card was then visible on the smartphone.
When you make these changes in settings, do you create a plan afterwards?
Settings are only saved once you create a plan, though it does sound odd that it would just disappear (unless you exited the app, or refreshed the page).