This location is no longer listed on evpass. It seems like AMAG replaced them with their own chargers.
On their web page https://parking.amag.ch/de/parkhaus/zuerich/opera.html it still shows a picture of the evpass chargers, but if you scroll down it says there are 17 charging stations, which is a lot more than evpass ever put there.
They never say the prices and I haven't been able to visit one yet to see how payment works...