MOTHER won't sell to me

I have 6800 echoes. I want to buy Preserved Containment: Expedient for 4125, yet nothing happens. No matter what I do- relogging, turning off all addons- it won’t sell to me. What do I do? I haven’t had an issue on my hunter but my priest absolutely cannot buy anything.

Oops. Sorry, Priest is Andorhal- Nymie.