It's definitely not special characters. All I am doing is trying to switch the "sign-in required" toggle - no text entered.
If I open the log in Chrome I see the following error...
logLevel: "ERROR"
message: "API Response Error: SAVEAPPREVIEWDETAILSRESPONSE"
stackTrace: "status code: 409 --- api correlation key: LAXXXXXXXXXXXXXXXXXXXXXE"
(Where the *** = a number - don't know if I should share it or not!)
Is there anything weird we might have in common? For example, I have two App Store Connect accounts on my apple ID.