Can you take a screenshot of the challenge to remind me which one it is?  I think there is a specific attribute on it if I am thinking of the same one

Is it one of the first ones you face? 

"Equip a Rare Support type Champion with 6 Life Artifacts"

The best way to do this one is just pick a bunch of throw away life set artifacts and pop them on your support based champ and then you can just destroy to remove them. Note though it has to be Life Artifacts and it must be a rare support champ and pay particular note of the gear level too. If you miss any of the requirements just once it wont count. 

Like RoseRoyal says above, it would be best to get a screenshot of the actual mission just to be sure we are talking about the same one. 

It  might  depend  on  stars  as  well-  make  sure  every  piece  is  the  right  set,  right  level,  and  right  rank.

Thanks  for  the  reply!  The  quest  was  glitched  and  stuck  at  2/3.

i  loaded  in  today  and  it  was  done .  

i

I  tried  every  set  of  +15  Health  and  on  three  separate  characters .  i  spent  1000's  in  removing  and  replacing  stuff  on  different  characters .  

Peace!!!

Ps  -  that  above  image  (for  anyone  that  cares  or  is  also  stuck!)  wasnt  the  only  combo  i  tried.  I  tried  many  on  many  suport  characters .