Recent changes to the Library of Congress z3950 target means that Koha systems with earlier configurations can not connect to the LC z3950 database and download bibliographic records. Updating, your Koha system with the new changes is however, simple and straight forward.
This is how to go about it:
Log in to koha from the administrator interface, (you will need administration privileges to do this) and go to ‘Koha administration’
Next scroll down to ‘Z3950 TARGETS’
Click on the Library of Congress (Name or the edit link)
UPDATE the connection information as follows:
Name: Library of Congress
Save your changes and restart your system.
Your Library of Congress z3950 should start working now as before!