Hi,
Can you check with your administrator that the external account exists and you have the rights to view it?
Can you also check if there are other Salesforce external accounts created on the instance?
Finally, can you tell us what are your server and console build versions? You can check this from Help > About in Adobe Campaign. Unwanted problems can sometimes occur when the server build version is too old or when the server and console version numbers are too far away from each other.
Let me know,
Florent.