Blizzard disablesthe Masherey API in January 2019. Therefore we migrated to the new Developer Portal at https://develop.battle.net/. Regarding this change, we have disabled our Battle.net Relay Service for Login, as HTTPS should be a standard nowadays and we recommend using encrypted connections.
For the Admins: you need new Client-IDs and -Secrets. Go to https://develop.battle.net/ for creating these.
For the users: it is neccessary for the user the delete the current connection with Battle.Net and to connect their EQdkp Plus Account again.