You will need to turn off iCloud Private Relay and have Configure DNS setting as Automatic under smu-wifi or eduroam settings to access the printers.
Please follow the steps below to turn off iCloud Private Relay and change DNS setting to Automatic:
Turning off iCloud Private Relay:
1) Open Settings and click on Wi-Fi
2) Click the i beside smu-wifi or eduroam
3) Turn off Icloud Private Relay
Changing DNS setting to Automatic:
1. Tap on the "i" symbol next to smu-wifi or eduroam.
2. Scroll down and click on Configure DNS.
4. Make sure the setting is set to Automatic.
If somebody wants, they can add extra DNS addresses manually by clicking on Manual and then entering their custom DNS addresses under the SMU default ones, but make sure the SMU default DNS addresses are not deleted.