Bill was paid late using Quick Pay.

LMG462

I used quick pay to pay a credit card (Lowe's synchrony). Quicken shows the bill was paid on the 17th, the website for the credit card shows it was paid on the 18th (and is now charging me a late fee) and my bank shows the payment was processed on the 20th. How do I find out if Quicken actually paid it late or if my credit card company made an error on their end?