Hello!
This error message means that your account did not accept the GDPR and thus got locked after some time. It c*ually be 'fixed' by the following steps:

1) Make a new character in another server

2) Fill in the GDPR information (Age and Country, it should pop up automatically to be filled in)

3) Accept the GDPR Policy by clicking the 'Cog' next to the 'Party' icon in the top right, then click 'Data Transfer Outside EEA' and then click on 'Accept'.

4) Wait 10-15 minutes

5) You should now be able to log back onto your old character and continue playing

If the above steps don't resolve it for you, the only option left is to make a ticket on the CS platform ('?' icon in-game or this link:https://support-center.oasgames.com/)

Thanks and have a great day!