War Caster 5.5 not an available option.

Recently re-speced a character from an 11th level bard to a 4/7 bard paladin. Previously I had been using the 5.5 war caster feat on the character, but when I went to re-add the feat it is no longer showing up as an option.

I've confirmed I turned off all the feat pre-requisites, and that my character still doesn't have that feat selected anywhere. But the 5.5 war caster isn't showing up as an option still. I even tried adding it manually using the "manage feats" button instead of the leveling up pages but it is no where to be found.

Any suggestions on how to resolve this?

Do you own the book that feats comes from (the Player's Handbook)? If you don't, and you only have access through content sharing, then the character needs to be in the campaign where the content is being shared for you to use that feat. If you made a new character instead of modifying the old one, the new one may not be in the campaign.

It's also worth taking a look at the Manage Feats button on the character sheet. Down at the bottom of that sidebar, there's a section called "Unavailable Feats". If you open up that section, it should list all of the feats that you have access to and why they're not available to select. If you don't see War Caster in there at all, it's because you don't have access to that content.