One out of two Yahoo accounts not syncing properly on Android

I have two Yahoo email accounts. I use a Samsung Note 8 with the default email app. I have always had both Yahoo emails there and they have worked properly up until April 16. Now, one of them syncs properly, and one doesn't show any emails after April 16 (or any before April 8). I have tried on multiple apps (bluemail & Yahoo mail app, as well as email apps on my wife's android). It works properly on the website, but when I go to Account info, under account security and 'secure your account with a yahoo key', it says I am not logged into any mobile apps (and on my other Yahoo account it DOES say I am logged into a mobile app.) Any thoughts on what happened to this email account? All my settings are the same, and I've tried changing my password. I'm really at a loss because one email account works on my mobile apps, and one email account is ONLY showing emails from April 8-April 16. It will not sync newer or older emails (but it DOES on the website). It has worked properly up until this point. Thank you.