Over the past week, I’ve tried 4 times to modify a WoW subscription both using credit card on file and by adding a new one. In all cases, the processes ended after clicking “confirm payment.” The “working on some things” spinner appears for 15 seconds and then an error occurs. I’m using Safari 13.0.4 on macOS 10.14.6. Today I tried again using Chrome and the transaction worked the first time.