@burnout426 Hello again!! I appreciate the help!! Well, let's go by parts.
Opera standalone installation? No. I didn't and I won't. As the only problem is this site (the extensions site), everything else, including the add ons I already have, works perfectly.
I'm accessing and sending copies directly from Opera. As I said, everything works except the above mentioned page.
Translate the error page? What is there to translate? "Cannot access this site." I think you've seen this on the internet, correct (https://forums.opera.com/topic/27385/message-this-site-can-t-be-reached-the-connection-was-reset)? It's the same page.
VPN? Man, I don't know how to use this, and so far I haven't seen much need for it.
Ctrl + Shift + i resulted in the image I'm uploading. Nothing has changed here. Should something happen?
This problem must be something very simple and silly. Because as I said, everything works normally, this site address is the only thing that doesn't work. How can it be???
Thank you again.