Error Adobe Digital editions

I have an e reader and a desktop computer. No problems with buying e books for my e reader. However when I try to download a acsm file / epub to my reader on the desktop it keeps asking to authorize the desktop with an adobe id, but doesn't accept the valid id:

After reading some threads in this forum, I downloaded digital editions on my desktop, and changed my password.

But when I try to authorize digital editions with the new password I get this error:

To come this far has taken an inordinate amount of time (I tried Adobe support chat, but after explaining everything at length and being re-directed and disconnected several times they referred me to the forum, without specifying further) and it is rather disheartening if you just would like to read an e-book and view the illustrations in colour.

Hope somebody will be able to help