United Netherlands - Achievment didnt unlock

[Aeternull]

Hi

So, today I decided to try and unlock some of the achievements in HoI4. First I went for 'Once More Mate' which requires occupying Gallipoli as Australia and it unlocked without any issue.

Now I went for 'United Netherlands' achievement and became facist, Belgium and Luxembourg both joined the Allies and started a war with Germay before my justification for war was complete. Either way, I joined the Axis, went to help Germany and once defeated them, I asked to control the states. Germany agreed and now I have Vlaanderen, Wallonie, Luxemburg, Brabant, Holland, Friesland states which are Belgium and Luxembourg.

But no Achievement. Anyone knows if I did something wrong or anything to that could help me get the achievemnt?

Thank you :3

[Nemoutis]

You have to own and control Belgium and Luxemburg. This means you have to annex them during the peace conference.
The fastest way to do this is probably to start over, ally Germany and declare war on Belgium and Luxemburg as soon as possible, so that the Allies don't join in.
Even if they do join, you can still get the achievement quickly. In my war against Luxemburg the allies joined in, but I got a seperate peace conference for Luxemburg after their surrender. (I really have no clue how the peace conferences trigger.

[Drevin]

For my achievement run, I didn't need to ally Germany. You can justify against Belgium and Luxemburg, and fight them by yourself. Just build up your army and perhaps the airforce too until the justification completes, and declare immediatelly after. While you wait, make sure you give your army an offensive order, so they can get full preparation bonus. Also while you wait, spend research and political power on army related stuff, not on production, as you only need to blitz through the enemy for a short time before you get both countries to surrender and finish the achievement.

[Aeternull]

Thanks guys. Got the achievemet after replying it couple of times.