Death knight creation

Unable to create a death knight on the Icecrown realm despite having a level 61 paladin on the Lordaeron realm. The prompt when trying to create a death knight states that a level 55 character on any realm is required to create a DK. I meet the criteria but I am unable to create a dk character.

you need a level 55 on the realm you want to make the dk on. only to bypass that is by donating and becoming a premium user.