Can't Login to mop

I can't login to mop, the realmlist is correct.... When I login on the 5.4.2 launcher shows frostwolf offline ( because im using a 5.4.2 c lient not a 5.4.8) However, when trying to login on a 5.4.8 client it says I need to use a battle.net account to login... so I try the email instead and it doesn't work.

your 5.4.8 client is setted for a different private server.
If you wanan play here you need to change realmlist but sometime it is not enough so I suggest you to download a new 5.4.8 client from here: https://www.warmane.com/download