The BrandMeister Network has changed its server list without notifying us. We've contacted them about this issue and we'll update the server list as soon as a fix is available. The server list will be automatically fixed without the need for a firmware upgrade on your device.
As a workaround you can enter a server address manually by enabling Advanced mode at the bottom right of the web interface and entering "brandmeister.hu" (without the quotation marks) at the Server address field on the Connectors page, Homebrew/MMDVM settings.
Sorry for the inconvenience.