Item can not be upgraded

[Cäpslöck-proudmoore]

Quoting Zorbix:

@Zorbrix-1669

Greetings,

We’ve identified the issue that’s preventing you from upgrading Season 4 gear and are working on a fix to resolve it. We plan on restarting all US WoW Servers to pick it up cleanly, which will happen tomorrow (Tuesday) morning at 7am Pacific (10am Eastern).

Apologies for any inconvenience.