I need to buy a license key. I'm from Brazil. Is there a representative available?

Thanks for your reply

I have an ATS25 max and noticed that the brightness of the screen is oscillating, it is very subtle but easily noticeable, has anyone else experienced this kind of issue?

I suggest you to review your antivirus settings, A-explorer is working fine here, I'm also use Windows 11 and my antivirus is Karspersky and had no problems at all.