Curious about this too. I recently pulled into two different EA stations only to have someone already there tell me the charger I was at was not working. Each time I tried the App/swipe combo first and it didn't work. Then I tried the iPhone wallet EA card held up to the rfid reader and both times the charger started. Both of these chargers appeared to be active and were NOT displaying the Out of Service warning on the displays.
I always use the wallet first and can start a charge within 20 seconds of exiting my car. The 4 that were down had "please unplug" messages and some timer on it (I took photos on my phone). I suspect you could get those working by calling the support number and have them reboot the charger. One was definitely Out of Service with a crazy error.
I picked the available one (as per app) and that started charging without issue.
I love free EA charging. Can't complain about it too much. I've used 200 kW in a month already and saved $90+ in public charging expenses. What I don't love is the locations and unpredictability of each charging session. I do meet a LOT of other ID.4 and EV owners and learn from everyone's experiences. There was one day that was a German car lovefest with a Taycan, e-Tron, and two ID.4s all parked together.