Sorry, even mine is fixed now !
Oh well mine isnāt fixed yet guess iāll wait more 
At the login, it said āHearth of Azerothā has been changed to āHearth of Azerothā with better stats.
Maybe what you can do is report a bug and they will fix it for you
I just make a lvl 120 boosted druid (from a lvl 20 one I had made already) using the shadowlands epic free lvl 120ā¦and I have a heart of azeroth at lvl 59 now but I cannot enter the chamber either. Also, she has very low dps for a lvl 120 with over 400 rating. The best dps I had was about 4K. Is there something wrong with my spells too? I realize that my gear is still horrid but stillā¦I can survive damage decently well while questing but it takes a long time to kill things
Closing this thread as the original issue discussed no longer applies.
@ Anaplasma, you can find a lot of handy guides covering the quests you need for your Heart of Azeroth as well as class guides and how to improve your DPS and such on the available community sites - two popular alternatives being https://www.wowhead.com/ and https://www.icy-veins.com/.