ikev2 vpn authentication error

Since a couple of weeks i cannot connect to mij ipsec ( strongswan ) vpn connection.

My iphone and my old macbook (2014) worked fine with my ikev2 ipsec vpn. But after updating the two devices I get " Authenticatie user failed".

As for my old ipad and my new macbook it works fine. My ipad is not updated, but my macbook Air is.

Can anyone help me out ?

Robert