A plugin Domain Monitor - MainWP WordPress Management doesn’t support for checking HR domains with expired domains. It show expired 1970 which is wrong
Support for .hr domain isn’t valid and validation show that expired to 1970. years.
You should check for HR (Croatia) domain using following sample of WHOIS.HR:
Code should be checked for expired domain:
Registrar Registration Expiration Date: 2022-08-28T22:00:00Z