FBS has got 4 different server names for trading accounts, which are:
|FBS-Real-Micro-Cent||Server name for Micro and Cent account|
|FBS-Demo||Server name for FBS demo account|
|FBS-Real-2 & FBS-Real||Server name for accounts other than the above|
Not server name but IP address
FBS actually provides server IP address as login credentials like below.
So you can just copy the IP address when you login to your MT4 account.
Although you can not Copy&Paste for MT4 webtrader, you may need to select one of them and find out.