Many people are having this issue with Capital one no syncing,  I have been dealing with this for months.  Everything they have told me to do DOES NOT work.  I've resorted to manually entering the transactions which is time consuming but better than wasting my time online with Quickbooks without any results

I GIVE UP

Honestly, it seems like Quickbook is making their desktop version worse so that people would use their cloud version. Watch more people will just leave quickbooks for Quicken or others because of their cost