You may have noticed a "Something went wrong" error when syncing with Amex recently. This is a timeout error. That basically means that it takes over 30 seconds for the information from your Amex account to load, so an error message appears. However, information should update in the background later. You may have to log out and log back in to see the info update. You can also check your Amex account on the "Accounts and Cards" page to see when it was most recently synced.
We are working on improving this.