I am building a character for a One-Shot and I am trying to add the item "Akmon, Hammer of Purphoros" to the character sheet and I can't find it anywhere.  I have the source it comes from purchased, all content turned on, and I have tried with and without the character being assigned and I cannot add it at all.  Can someone please help me figure out how to add this to the Character sheet?

Is your character proficient with warhammers? If not, it won't show by default since the character cannot attune to it. Uncheck "proficient" box and it can then appear.

If you have the book (full book, not just compendium-only version) purchased check your entitlements are in sync here: https://www.dndbeyond.com/account/marketplace

the character is proficient with warhammers
i have the full version of the book
it just doesn't show up

Do you have "Magic: The Gathering Content" enabled? Check the  Sources toggles in the HOME section of the Character Builder.

I have everything enabled

I got it
I rebuilt the character and it made it work