I would like you to de-authorize ADE and re-authorize ADE using your adobe ID using the below method :
• Launch ADE.
• Press Control+Shift+D (Windows) or Command+Shift+D (Mac)
• You will get an option to De-authorize or Erase Authorization(depending on your ADE version), click it and you are done.
• Exit and re-launch ADE.
• Go To Help-> Authorize Computer.
• Enter your credentials and authorize ADE.
Check if you still get the same error. If so, then the below article should help.
Also, make sure you have the latest ADE 3.0 version installed. If not, you can download the same from the below link.
Let me know in case you still face the same issue.