I made a homebrew item for the monk.  It is essentially bullets for a sling that deal extra fire damage.  I have four people in my campaign and I can bring the item up in 3 of the players inventory but cannot see it when I try to add it to the monk.  The monk already has one homebrew item in his inventory.   Any ideas what is going on?

Item: https://www.dndbeyond.com/magic-items/8106437-fire-bullets

Monk: https://www.dndbeyond.com/characters/117870352

Please see the General Homebrew FAQ #5: (https://www.dndbeyond.com/forums/dungeons-dragons-discussion/homebrew-house-rules/131411-a-homebrewers-how-to-faq).

Thanks for posting, but I tried all that already.

First, make sure the homebrew in question is in your homebrew collection. Only homebrew specifically in your collection will be available to add to a character sheet

It is.

Then, on the Home tab of the character builder, or on the Character Settings sidebar of the character sheet, the toggle next to “Homebrewed Content” needs to be on (red, to the right).

As I said, he already has a homebrew item

If the Homebrew in question is a subclass, is your character at the correct level to select a subclass? Only Clerics, Sorcerers, and Warlocks select their subclasses at 1st level, the rest all select their subclasses at 2nd (Druids & Wizards) or 3rd level (everything else).

It is not a subclass.

If the Homebrew in question is a weapon or armor set, and your character is not proficient with the item, make sure that the "Proficient" box is not checked under the search parameters.

 The item is a wonderous item.  Every other character in the same campaign can see it.

Okay, then in that case you should both make sure that your Account Entitlements are in sync: (https://www.dndbeyond.com/account/marketplace).