account has been locked / location that you don't typically play

Each time that I open POE, this message appears, and I need to send a code to my mail before unblocking my account. How can I make it stop?

This typically happens when you change physical locations, this is a security measure so that someone "overseas" for example cannot just sign into your account without it being locked and subsequently you having to unlock it via accessing your email.

This happens when your IP address changes. Some ISPs are notorious at changing your IP address a lot, others rarely. Depending on ISP, you can get a fixed IP address as an option, but it usually costs extra.

You can ask GGG to disable that security feature by contacting them via email, however - 1) bear in mind they will never restore anything that's lost in the event of an account compromise, 2) their response times are currently weeks to months depending on the specific type of issue; not hours or days. If you want to do it, the address is support@grindinggear.com.

It can speed things up a bit if your initial email is from an address that's associated with your Path of Exile account, contains your account name including the four-digit discriminator at the end, and you mention 2 or 3 character names as well. Otherwise you'll be waiting just to get a response asking you for that information. Personally, given the lack of 2FA support, I wouldn't rush to remove what scant protection is currently in place - but hey, it's your account and your decision.