Hkn98
Thanks for testing that. Since a new browser and a different Cart-ID show the same error, a local browser glitch on your side is likely ruled out.
The issue seems to be hidden deep within the Sunrise backend system. It could be a simple database error with your new account configuration, or an automated internal contract check (credit check?), which is blocking the order process at the final step.
Maybe you should try contacting the sales hotline (0800 707 504). Ask them to check if your account is fully cleared for device plans, or if they can manually place the order for you. Alternatively, if you have the chance, you could also visit a physical Sunrise shop directly.