Hello,
Can someone from the Xcode or macOS team please have a look at Bug Report #33586920? Since the release of macOS High Sierra I haven't been able to add my developer account to Xcode or use Application Loader. When I add the account it says "x@x.com could not sign in.".
I've been in touch with Apple Developer Program Support countless times (ticket 100314344378, 100352482264 and 100310235401) and they have tried to do some changes to my Apple ID, but with no luck. The feedback I received last time is that they don't have access to the bug report and cannot investigate more and suggested I should ask for updates in the original bug report - but I havent received any updates since August 10th 2017...
The only way I can ship updates to my app is to run a virtual machine with macOS Sierra, where I can still login.
Regards,
Espen