If you are in the config.txt and editing it, here are the steps to "comment out" a stanza:
T ABC123 U https://www.abc123.com HJ www.abc123.com DJ abc123.com
Then put a pound sign (#) in front of each line so it looks like:
#T ABC123 #U https://www.abc123.com #HJ www.abc123.com #DJ abc123.com
EZproxy will not read the lines.