Facebook Sharing Debugger is returning a 403 error when testing my website's links

Question

For a while now, I've had a problem with Facebook's Sharing Debugger. When I try posting the links to my Wordpress site to test/precache them for sharing, they return code 403. It mentions that I must allow "facebookexternalhit" on my robots.txt file, which is already allowed.

Whenever I scrape a page of my site with Facebook's sharing debugger, my server replies with code 200, verified on the server logs, but Facebook reports 403. I tried Iframely's debugger, and it works like a charm.

Whenever I scrape the robots.txt file, I get code 206.

My website is https://www.pokecenterblog.pt.

I did the following:

• disabled all Wordpress plugins.

• cleared the Wordpress cache.

• specifically allowed facebookexternalhit on robots.txt.

• tried disabling the firewall.

• tried disabling bot protection.

• asked the host for help.

• asked Facebook for help, both on their Dev forum as well as their Facebook group, with little to no help.

• used Facebook's Troubleshooter (cUrl command), which returns code 200.

What do I need to do to get that sweet code 200? I'm honestly at a loss. Please help. Thank you.