Hello everyone,
Current news is that the account restrictions are for anyone that’s has played less then full 30 days on the account. If you’ve played longer then those days, try staying logged out for 12+ offline hours.
If the issue persists: They’re looking into it.
There may be an issue with players who started a subscription in February because it only had 28 days. The US devs are aware and checking if that can be fixed.
Edit: Additionally since the EU blue post, this restriction is also valid for the Classic Era and SOD realms.