What's wrong with EA.com account and Polish tld?

tl;dr Origin client for Windows 10 blocks creation of child account claiming that provided parent’s email address (which belongs to an existing account) is invalid. It seems that the problem is because that parent’s email address is in Polish (.pl) top-level domain (ccTLD).

Does anyone heard anything about such weird problem? Is this something common or is it only me?

What should I do in this case, if I don’t want to / can’t use different email (i.e. with non-Polish ccTLD)?

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I cannot enrol new child EA.com / Origin account because it claims that my (parent) email address (that I’ve been using for past 17 years) is invalid.

As I managed to figure out, the .pl (Polish top-level domain) is the problem. My Gmail’s address passes without any troubles.

The story goes as:

1. I have tried to register new account using newest stable version of Chrome browser for Windows. That failed (left above). For some reason using exactly the same URL I managed to enroll an account using Edge for Windows 10.

2. Then my daughter installed Origin client for Windows 10 and tried to register child account, by providing my email address and her password (as instructed here). And we hit the wall for the second time.

This is twice stupid. Not only EA stuff (website) claims that a perfectly valid email address is invalid, but also EA software (Origin client) claims that already existing account’s¹ email address is invalid.

Is there anything I can do in this case? Except for using another email address (i.e. without Polish ccTLD), which I’d like to avoid as much as this is possible. How to enroll a child account into existing parent’s account if Origin client claims that parent account’s email is invalid?

I did some research, but all that I managed to find out was some dully post that reports above, but brings no resolution to described problem.

¹_{I can login to my account anytime and when I am doing so, it is magically no longer invalid.}

EDIT: The issue is with Polish (.pl) domain in general. I have five .pl email addresses and all of them suffers this way. I have a single non-dot-pl email address and it goes without any problems.