I'm trying to authorize my computer in Adobe Digital Editions 4.5.12, but I keep getting: "Incorrect login ID or password for the selected eBook vendor."

I am having the same problems. and with ByteBooks all I get is a 403 error code. is the problem adobe or what?

Same problem. I’ve tried everyting

What I did to make it work was to create an account at ByteBooks as Monika mentioned. Then  Authorize your computer using your mail address and password for your ByteBooks account. Make sure not to use any foreign characters in your password, I used some Swedish characters åäö which did not work. 

You should still use “Adobe ID” as your eBook Vendor.

Try follwoing these instructions:
How to export books from Google Play to your computer - Google Play Help
I had to create completely new account on ByteBooks because it was adamant my adobe account does not exists (it does...). But with new ByteBooks account I was able to finally authorize my computer in Adobe Digital Editions :)

I have exactly the same problem since yesterday evening..

I can sign in to my Adobe account in the browser without any issues, but Adobe Digital Editions always says my Adobe ID or password is incorrect when I try to authorize my computer.

I've already reset my password, reinstalled ADE, deleted the authorization data, and verified that I'm using the correct Adobe ID, but nothing has helped so far.