From my battle to our war, MMORPG MIR4.
Greetings, This is MIR4.
We have confirmed an issue that linking with Facebook account is not available at the moment showing an error message.
This is not an issue of MIR4 and it is due to the linking error with Facebook itself. You will be able to use our service when the service of Facebook gets normalized.
We will do our best to provide stable service.