Cannot login to Spore (on Origin)

So, I had purchased Spore on Origin a long time ago, before 2014. I think this is relevant, and I think what may also matter is that I originally registered my EA account with an old e-mail on my own domain (EA doesn't seem to allow own domain e-mails currently). I have changed my e-mail to a gmail as an attempt to fix the below issue, but it didn't help.

Inside the game, I am unable to register. The error message is "An unknown error occurred during registration. Please try again." Trying again, obviously, doesn't work.

This is not a network error, because if I type the wrong password, I get "The email address and password don't match anything in our system."

If I try to login, I get "There was an error connecting to the Spore servers [...]".

I'd like to note that if I login on Spore.com, I get the "welcome" message, like if everything was normal, but if I open Sporepedia, I get the message "To fully experience the Sporepedia, you must be logged in" in the sidebar and "You must be logged in to leave comments " in the comments of every creation.

This seems like an issue on Spore servers to me, did anyone else have the same issue? I am unable to find any help for this exact problem. Thank you.