It would be very helpful if you could give some specific URLs here at ibiblio and the HTTP response codes you’re getting. If you know how to do that, just reply and ignore the rest of this. If not, read on…
An easy way to do that is to use curl, which is available for all the major operating systems and installed by default in various linux distros and on Mac. Here is an example shell session on a Mac where the terminal prompt is a percent sign ("%"):
% curl -D - http://ibiblio.org
HTTP/1.1 301 Moved Permanently
So what I did here is use the ‘curl’ command with the “-D” switch (“dump headers”) followed by a “-” to tell it to put those headers right back to standard out instead of to a file, and then lastly I gave it a URL. The next four lines are the output after I hit return, and that first line starting with “HTTP/1.1 301” is the response code. If you’re on Windows, you may be able to enable Windows Services for Linux if it’s not blocked by your employer’s group policies on your machine. You’d then go into the Microsoft store and install a Linux distro such as Debian. That would be by far the fastest/easiest way for you to get a linux environment on your machine where you’re having trouble. There are other ways to get HTTP headers, and possibly somebody will chime in here with one that works better for you.