At first, I also had an error, but it was 433 which stated that there were already 100 users on the same line, and I was to try again, When I tried again, it worked...
The server 500 error means that an internal problem has occurred on the server at the other end - nothing you can fix - as John has said retry again later.
I use Audio cleaning Lab 16 and this function used to work but some time back I started getting this same message. This probably stared when changes were made to the Freedb web site. The syntax required to access the site must have changed and this has stopped cleaning lab's ability to auto access the Freedb data base. This is very frustating as getting track listings to import easily has stopped. I have had to resort to using "Get track list on line" function from CD/DVD dropdown tab, manually search for the CD track list, open the "disc ID" then cut and paste the url into Audio Cleaning Lab. Not very satisfactory, very long winded and quite clearly an "Re-work Update" needed from Magix to