Why, after transferring a site to another server, loading text with the file function from one site began to often lead to a 400 Bad Request error?

Question

PHP

There is a site with this code on one server:

$loremIpsum = array_map("strip_tags", file("http://loripsum.net/api/1/short/headers", FILE_IGNORE_NEW_LINES));

Works without problems.
I moved the site without any changes to another server and often began to give a 400 error. On the first server, everything still works fine.

file( loripsum.net/api/1/short/headers): failed to open stream: HTTP request failed! HTTP/1.1 400 Bad Request 2

Both servers are ubuntu virtual machines in virtualBox.
What could be the reason?