Same error here: lookupMainFuncAddressInMachHeader:71: Invalid Swift entry point data lookupMainFuncAddressInMachHeader:77: Swift entry point addres could not be determined. Only started occurring since upgrade to Xcode 12.

Having the exact same issue, just started tonight. Nothing different in my app to the way it was 2 days ago. Just a totally unhelpful error code 15 (serverRejectedRequest). Can see my container fine via CloudKit console but the app is not able to connect. Evening of development lost, very annoying.

Same for me.