Fonts not adding from character dropdown

Ensure you're logged into Creative Cloud Desktop and it's open - and also ensure you're logged in online in Creative Cloud online .

If it's not working - then log out of Creative Cloud Desktop - Log out of Creative Cloud online - in InDesign go to Help>Log out

Restart your computer - then log back in everywhere

This usually resets the communication between InDesign, Creative Cloud and the online Fonts. 

You could always test too by going to Adobe Fonts and see if you can download the font there. 

Maybe doing that will get your InDesign and Fonts talking to each other again.