Charging issues- home and public

Hi. We have a chargemaster charge point installed and our Zoe always comes up with an error message (charge stand issue) , red lights and won't connect. We've had the charger serviced by an independent engineer (bppulse won't support it any more) and the supply is fine. It also charged a friend's vw ev.

We're finding public chargers variable too. Some won't connect at all and others will connect but then stop charging . Even though the app says the charge is still ongoing.

Any thoughts on what's going on? Or how we can resolve it? The dealer says the charging is fine but I don't know what checks they did as it was in for another issue.

I don't want to install a new charger unnecessarily, but I need to be able to charge the car reliably!