Bought developer licence.
Bought another developer licence for a Company.
Moved the app to that Company and Deployed it OK (faint memory of fading nightmare).
Made first update to app (in iStore OK).
Gave that Company my iTune login and pw (and they changed the pw) and then they registered me as a developer with them.
Tried to update the app again (using my new login + pw) and all went well untill I clicked on "Application Loader.app" - a quick error message flashed on and off and now nothing happens at all when it is clicked on - the app is displayed permanently in iStore (iTunes Connect) as status: waiting for upload.
This is the exact same Macbook used originally. What has changed? Or, what exactly is the relationship between "The System" and a developer?
This is what I discovered, by poke-and-hope:
a) That Apple ID that you use for iTunes (and for the app) is used by Applications Loader.app, behind the scenes, along with that Apple ID's password. In other words, once you have created that app and then uploaded it to iTunes Connect, then both app and your iTunes Connect account are locked together by the same Apple-ID and the same pw.
b) If, in a blind panic you lock yourself out of iTunes by frantically typing the wrong pw in more than three times so that a red message always appears saying "This apple ID has been disabled for security reasons." then don't panic even more, just press the "forgot password..." button, you can recover via the usual email or by answering your own security questions. In other words, that message is just a scare-device (or Apple were forced to "disable it" otherwise anyone can disable any Apple-ID they like!)
c) If, you delete your Apple-ID (by creating another user with admin rights and then logging on via that) and then discover to your horror (or wonderful realisation) that Application Loader.app has noticed that it is now missing, you can, you absolutely must, put it back again by creating another admin-rights user and then loggin to that one and change the apple-ID back to the one you deleted (the original one that is also the original-developer-licence-of-the-app), and provided you match it all up properly including the same original pw, then Application Loader.app will acknowledge it correctly and upload your apps again.
d) The reason for lack of any sort of error message in second part of 7) above was because I did not realise that you gotta right-click->quit on the Application Loader.app icon that appears on bottom bar, before you can then click on Application Loader.app in Finder again)(I am still getting used to Mac). When it loads the second time, then a dialogue pops up (and stays there) saying "Directory Services reported the following error: Your Apple ID or password was entered incorrectly. (-20101). It is all so obvious now but back then, I had forgotten exactly what an Apple-ID was let alone that I owned one of them (actually I own two of them, one with each developer's licence, I think?) I doubt I will forget what an Apple-ID is now! At least not for a month or two anyway.
Go to the Application Loader menu
Window > Run Setup Wizard
You'll be prompted for your AppleID and Password again. As you've found using the wrong authentication can cause problems.
I have the same problem "Directory Services reported the following error: Your Apple ID or password was entered incorrectly. (-20101)"
I fixed it in the following way:
Hope it helps you.