Specify User-Agent
Once in a while I have experienced not being able to access some site using curl, but it works in your regular browser.
This mean that somebody blocks curl since they assume it is a bot or something similar.
Telling the website, that your curl is as very easy and curl can pretend to be another client, which demonstrates the stupidity in attempting to block based on the User-Agent.
curl has a User-Agent along the lines of:
User-Agent: curl/7.79.1
All you have to do is specify another User-Agent like:
Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/94.0.4606.81 Safari/537.36
The following command should do the job:
curl -I -X GET -A "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/94.0.4606.81 Safari/537.36"<url>
I am by no means a hacker, but this is like the cheapest and easiest hack in the book.
And this is just circumvention of client discrimination.