@awangzd As I know, can only reset the password through serial port. And you need to access the bootutil of the switch. You can refer to the FAQ. https://www.tp-link.com/en/support/faq/2124/

@alexman Have several opinion for reference. 1. The client IP should be public IP address. If you cannot make sure what public IP address your client uses, you can fill 0.0.0.0. 2. The IP address...

@Fubb26 It seems that R480T+ has the table of authentication status. Maybe can check if the account was already authorized.

@AlistairD Suppose that you have two WAN ports. Link backup and loadbalance will not exist at the same time. Because link backup will make the backup WAN offline. So only one WAN will be online so...

@AlistairD Suppose that WAN1 is primary WAN. WAN2 is backup WAN. Gernally WAN1 is online and WAN2 will down. When WAN1 is offline, WAN2 will be UP. When WAN1 get back to work, WAN2 will be offline.

@Fubb26 It seems that each account has the settings of maximum users. Did you set maximum users as 1? If so, maybe can check if the account is already used by others.