Ikea Brimnes daybed slatted frame crooked, what assembly error?

Hello dear users,
After searching the internet and unfortunately not finding anything that helps me, I came across this group. I hope you can somehow help me.
I have assembled the entire Brimnes bed and everything seems fine so far. But I noticed that the rails for the fixed slatted frame simply don't fit in height. The front part is 7 cm lower. According to the instructions, I did everything correctly, and I noticed that the holes on the side pieces are drilled much deeper.
But they are pre-drilled?!?
Do you maybe have an idea what I did wrong?
Thanks a lot in advance
Sandra

Hi,

I don't have Brimnes myself - but did you perhaps assemble the frame "upside down"? The front rail has to be higher than the rear support because the slats are attached from underneath at the front (and rest on the rail at the back).

Otherwise, take a photo of the side panels in the assembled state where the position of the rails can be seen (upload it to the gallery here in the forum).

Regards, IKEA friend