Bug: Netherwing Questline Stuck (Can't get quests from Mordenai)

Hello everyone,

I’m Horde. After Zuluhed’s Key → Ally of the Netherwing, no more quests appeared. My reputation tab shows Exalted and I already got the achievement On Wings of Nether. But Netherwing NPCs are still hostile, and I cannot access the vendor.

Is this a known bug on this server? If anyone has faced a similar issue and found a solution, could you please let me know what I can do? I'm hoping to get the Netherwing Drake.

Thank you in advance for your help!

Best regards,