I had to do an emergency Server reboot today to fix an exploit that has been discovered.
It was possible to upgrade rares with less than the required materials with 100% success rate (like using 1 or 2 G4 to make a G5 instead of 3).
The issue has been patched and will no longer happen.
However, several players have apparently abused it. I have tracked these and permanently banned any character that abused it. I have also banned any other account they own.
If you think you have been unfairly banned, I invite you to submit a ticket at https://dragonraja.eu/support and I will have a deeper look at your character.
Sorry for the inconvenience.