USG60 V4.35(AAKY.3) / 2020-02-26 17:00:28
Initial Setup Wizard - Port Forwarding - Click the Edit icon next to Client List
CLI Number: 3
Error Number: -31042
Error Message: 'The interface name is not accepted.
Welcome to Zyxel community
Can you share what interface name are you current using?
Is there any specific character in it?